I mentioned in the thread for the "useless sharptooth" that I've spent 70% of my time - probably more now that I think about it - in the TLBT fandom with my head buried in the sharptooth aspect in the series. Of that 70%, I would wager that up to 20% of that time has been spent mocking "the biggest and meanest sharptooth of them all".
Yeah, I'm not gonna beat around the bush, I think Red Claw stinks; for as much as they try to build him up - I've already mentioned Chomper's description of him but there's also the fact that the reason Chomper and Ruby are in the Great Valley in the first place is because their parents want them to be safe from him - he doesn't really do anything more than roar, try to look intimidating and miserably fail to catch a few little kids six times over (his last appearance isn't even him threatening anyone, it's just him out for a stroll in the vicinity of Hanging Rock). His minions don't fare a lot better; Screech and (usually) Thud are no more interesting than any of the other bland post-art shift sharpteeth are outside of 'Escape from the Mysterious Beyond', which gives spotlight to Thud and is actually sort of interesting.
1.) Because the TV series doesn't elaborate on the sharpteeth's personalities too much past that welcome glimpse at Thud, I'm going to veer into headcanon territory here: I don't think Screech shares his honor and I'm certain that, if they ever tried to pull anything like what happened in that episode and Red Claw found out, the tyrannosaur would have their heads in a heartbeat.
2.) I see their failures as a blend of both... mostly incompetence, though 
I actually have a little something for this (I say "little"); something I started in May that was/is still intended as the opener for a larger story about what happened to Red Claw after the events of 'The Hidden Canyon'. Unlike the other unfinished story I've shared here, I think this works on its own as a silly, short one-shot; have you ever wanted to read 833-word description of what was going through Red Claw's mind when Topps launched that one treesweet down his windpipe?
Red Claw could only handle so much.
"He-hey, that looks like fun! Toss me a piece," an unintelligible voice had grunted before this moment.
There were a slew of words that could have been used to describe the sensations that ran through Red Claw on that fateful day. Anger, frustration, humiliation, bewilderment...
None embodied what was surging through him quite as well as "disgust".
Treesweets, especially of this kind, were never meant to be be eaten by sharpteeth. They were tuned to entice leaf-eaters to eat them, digest them and pass along their seeds after all was said and done - these fruits in particular were loaded with sugars and acids and had a smooth, creamy texture that greatly appealed to herbivores, bolstered by an intensely powerful, pleasant aroma.
Sharpteeth were different beasts, with dramatically different tastes from their flat-toothed cousins and ways of taking in senses such as smell and taste. To the carnivores, the smell of the treesweets alone was enough to deter them from wherever they grew - what the leaf-eaters regarded as a delectable precursor to a heavenly meal registered as unbearably sweet to the carnivores, so strong that it could make even a young one's nostrils feel as if they were burning if they were present in great enough numbers. Just the Great Valley's luck that there so happened to be an entire grove of these aromatic fruits' trees growing in the adjacent Hidden Canyon, and just Red Claw, Screech and Thud's luck that the valley's resident seven children had stripped the canyon of the majority of its deterrents.
That "luck" had ultimately led to this point. A rain of treesweets upon Screech and Thud and, in Red Claw's case, a once-in-a-lifetime sample of one of the accursed things.
The taste of the treesweet was difficult for Red Claw to comprehend. In fact, it had taken a moment for his mind to register that the big threehorn had launched one down his gullet in the first place. For the ever-brief period of time that its taste was the only thing that struck him, he, having only ever consumed the flesh and body parts of other animals and having spent a good portion of his early life fighting for scraps of varying quality, could best liken the texture to that of an eyeball - unpleasantly soft with a vague gelatinous feel - and the taste itself to the stomach of a yellowbelly - too sweet for even the most hyperactive fastbiter chick.
If the taste were not repulsive enough, the following sensation of the treesweet's scent filling his mouth, overloading his nostrils and sabotaging his hyper-sensitive olfactory bulb would have been enough to send a smaller sharptooth into a coma. His split-second decision to swallow the thing only sealed his fate.
Tears streamed down the tyrannosaur's cheeks as his face began to pale and his lower jaw trembled. He could barely even curse inwardly at himself, his tiny brain too wracked by the agony wrought by the fruit. Before he had the chance to collapse by himself out of sheer shock, the longneck that accompanied the threehorn in his fight against he and his fastbiters - all but forgotten in his moment of weakness - lashed his thick tail at the sharptooth's ankle, sending him tumbling to the canyon floor with a resounding crash.
Lying on his side, Red Claw had a chance to recuperate slightly. His face was slathered in vivid, pink, pulpy juice from the treesweets, products of the barrage that had preceded the incident that had fried his brain and forced his fastbiter subordinates to retreat, but the feeling in his head was starting to fade, albeit barely. Though his vision was typically quite acute for a sharptooth with impaired binocular vision, at the moment, it was difficult for him to make out much more than vague shapes and tiny, floating "stars". A horrid, indescribable aftertaste lingered inside his his mouth. Tucking his scarred arm under his multi-ton bulk and not raising his head from the ground, he opened his eyes and made an effort to look out in front of himself.
Oh, treestars, what did I just...?
Even with his vision blurred, he could make out blobs of yellow soaring towards him from the direction of the longneck and the threehorn, and even in his dazed state, the sight was enough to make his heart drop into his stomach.
With all of the strength he could muster, Red Claw rolled himself onto his belly and pushed his huge body off of the ground with all four of his limbs, turning to face his attackers one last time.
This won't be the last you see of me! I swear it! he bellowed, before lumbering off in the opposite direction, his words falling upon all of the victors of the battle but one as a meaningless roar. Many yards ahead, Screech and Thud bolted towards the canyon leading back the Mysterious Beyond. He growled to himself and picked up his pace to keep up.
That. Was. HILARIOUS! Thought I was in for a treat when you asked "have you ever wanted to read 833-word description of what was going through Red Claw's mind when Topps launched that one treesweet down his windpipe?" To think you got so much quality mileage out of such a short scene!
I have to agree on your initial points concerning Red Claw, Screech and Thud. They really don't live up to the hype, and seem to spend the vast majority of their time flexing intimidation. Akin to your head canon, I ended up portraying Thud as the more honourable of the two in my writing, not that he makes it very obvious most of the time. I also attempted to paint Red Claw as something truly formidable, with a few twists that set him up as more than a mere predator who 'randomly' bumps into the Gang of Seven. There's nothing 'random' about him. He's actually ... well, I won't spoil it. Here's a clip of my own, if you want an idea:
Cera accelerated as Red Claw stood in a stupor, still stunned by her horrendous insult in the sharptooth tongue. She was almost fully grown, but he was nearly twice her size. Nonetheless, she was ready.
Every day of her training had his name on it.
Red Claw's shock turned to outrage. He didn't roar, didn't growl. He simply gestured Screech and Thud to attack the longneck before standing there in silent fury. Did he expect her to run into his jaws? He had another thing coming!
Cera was at the edge of pouncing range when Red Claw lunged. She stopped abruptly, drawing back. His mighty jaws crashed together like a thunderclap, jarring her ears as they fell just short of her. The threehorn screamed a battle cry as she smashed her horns into the side of his chin. The impact sent a shockwave through her skull. It felt good! Time seemed to slow as Cera etched the moment into her memory, relishing the bafflement rippling across Red Claw's face as his head lurched. She bet no threehorn had taken him down in one hit! Red Claw seemed to flash her a glare as he continued to reel. Wait ... he wasn't falling. He was no longer reeling either. He was turning. While his head pivoted away with the momentum, his tail blazed towards her. She almost didn't see it. There was no time to dodge. No time to counter. Cera could only crouch low and brace herself.
Half the breath blasted from her lungs as Red Claw's tail met her side. The strike arced upwards, like a golfer's swing, specifically intended to overturn her. Trepidation spiked through the threehorn as she found herself toppling. This wasn't supposed to happen! Once she lowered her centre of gravity, no one had knocked her down in one stroke! Not Chomper, not even Littlefoot! Maybe that was the problem. Littlefoot and Chomper sparred with her as friends.
Red Claw fought her as a killer.
Upon hitting the ground, Cera skilfully rolled with the blow, ending up back on her feet. She could scarcely stand before Red Claw's teeth latched around her horn. He was fast. So was she. The threehorn hammered his muzzle with her forepaw. The horn slipped free. After knocking his head skywards with a headbutt, she rammed his stomach. He slid back, but didn't drop. Why wouldn't this brute go down?! Then came the realisation. She recognised the feel of the hide against her horns.
Red Claw had stone scales.
Unforgiving jaws clamped her back: easily the most painful, terrifying thing she'd ever felt. If not for her own stone-hardened scales, the battle might have ended there and then. Instead, Red Claw flipped her onto her back with a jerk of the jaws. He went for the underbelly, stumbling away when her hind paws found his face half by practise, half by panic.
She hurried to her feet.
The sharptooth shook off the blow and exploded towards her.
He froze, jaws wide.
Cera had perfectly poised her three-foot horn to meet his mouth in the most damaging way possible. A few inches later and he would have made a grave mistake.
Red Claw backed away, tilting his head as he gave the three horned conundrum a calm, contemplative stare.
"Aww, what's wrong?" Cera asked in her most patronising voice. "Is the big, bad Red Claw scared of me? Booo hooo!"
The sharptooth didn't react. His silence was mildly unnerving. Much to her surprise, his posture seemed to relax as he yawned. It almost looked as though he were losing interest!
Cera subconsciously slackened her muscles as she stifled a yawn of her own. Oh, great. It was contagious.
He blinked lazily, giving the sky a semi-wary glance.
She blinked as well.
The moment she opened her eyes, Red Claw was silently, ravenously, surging at her. The moment she snapped to attention, he launched into a confusing zigzag. Instead of colliding, they converged in what looked like an intricate dance. Back and forth, left and right, neither landed a blow as Red Claw strained her reflexes with incessant attempts to get by her horns.
...
Thud leapt before Littlefoot's tail snapped beneath him, the thunder crack jolting his bones and robbing his hearing for a split moment. He wasn't expecting the longneck to sharply raise his tail mid-swing, smacking the fast biter high above the ground.
Screech pounced from behind, only to find himself halted inches from contact when Littlefoot's tail snatched him from the air.
Lifting the nonplussed fast biter so that they were face to face, Littlefoot gave the predator a flat smile.
Thud slumped. Yet again, the longneck had him. He supposed he could see the sardonic humour. This time, he was sure he'd be squished.
To the fast biter's utter confusion, Littlefoot set him down with a pat to the head for good measure. Thud blinked blankly, having no frame of reference for what was happening. The longneck wasn't being friendly. He simply gave a deadpan stare as though waiting for something to happen. Hold on a minute, where was that shadow coming fro-?
Thud was beginning to look up when Screech crashed down on top of him.
Littlefoot examined his handiwork. The fast biters seemed down for the count. His job done, he rushed to Cera's aid. Scarcely had he left before Screech cut the act and climbed off of Thud. The fall might not have rendered them unconscious, but they couldn't help but groan from the soreness. Thud quietly snarled after Littlefoot.
Screech chittered, telling Thud that they should go after the others while the longneck still thought they were incapacitated.
Thud argued that he wasn't done with the longneck: not after the smart-talking mound of meat made a fool of him twice!
Screech hissed, insisting that Thud needed no help to make a fool of himself. If they really wanted to spite the longneck, they had to go for his weak spot: his friends! Red Claw could take care of himself.
Thud sneered at their alpha, sure not to be seen. It would be a hollow victory. The longneck wouldn't be alive long enough to see what happened to his friends.
With a malicious purr, Screech assured Thud that the longneck didn't have to see it. They could state the grisly details of their intentions at a distance.
Perking up somewhat, Thud bobbed his head in agreement. After pausing to scan the sky, the two fast biters rushed after the departed dinosaurs.
They would have to act fast, Thud warned, before The Daybreaker found them.
Check out more of the story at:
https://www.fanfiction.net/s/13516136/1/War-Before-Time-Part-1-Mentors-of-Yesteryears