Here's what the gang's appearance and personalities would be like:
Littlefoot: Same type of rex as Chomper, slightly bigger than him, and still has the leader role of the gang.
Cera: Fast biter, Has the same kind of ego (Fastbiters are the best.) Tries to outhunt or out-anything the rest of the group.
Petire: Sharptooth flyer (Forgot the exact term.) Since in the alternate reality, he's a predator, he isn't as nervous, actually quite brave, but prone to do dumb things (though he's not dumb.)
Ducky: Swimming sharpotth (Again, forgot the term, could someone remind me.) Due tobeing bound to water unlike the leafeater version, she's not with the group all the time. She's probably the calmest of them all.
Spike: belly dragger, suffers same lack of speech. Likes to swipe the rest of the gang's food sometimes, possibly the physically strongest, and though he can't talk, knows a lot, and good at coming up with plans.
Ruby: Also a fastbiter, though different color than Cera. Since there both sharpteeth now, has romantic feelings for Chomper. (Might make her his girlfriend, and his former sharptooth girlfriend just a friend.)