I haven't seen the movie yet but I pretty much know what happens, and I know all the iconic scenes, so I'll try my best.

1) One of the major themes of this film seems to be hero worship and (as depicted in the case of Grandpa Longneck) how it is not necessary to idolize distant figures as heroes, as heroes exist all around us in our everyday lives. Do you agree that this is a major theme of the film, and do you agree with that premise?
Littlefoot deffinetly looked up to Doc. But since I never watched the film, I don't know if this inspiration of his was the main bulk of the film. I'm sure they had some bits here and there where Littlefoot and Doc shared time together. And yes, I do agree with that statment. Though, I know it's hard to recognize every hero.
2) What are your thoughts on the “Legend of the Lone Dinosaur” song?
I'm with SRFG, that song is a hecking bop. It's one of the few songs that I liked in the tv series.
3) In terms of the questionable things that the gang has done in their lives, where does ‘Littlefoot going into a sharptooth’s mouth in order to take one of its teeth’ rank? 
By far, I feel like they can't do any worse than this. In the later movies, I think he would reconsider things and find a safer way to restore thier luck or whatever.
4) What are your general thoughts about Doc as a character?
Oh my treestars, he has got to be one of the most interesting characters in the whole franchise! His personality is so unique, he's like a southern cow boy dino! His design is kinda cool two. I think Doc is one of the few characters that have perminint scars. Well, normally you see them on the villans, like Red claw, but to put that element into a good guy character means something more. He's deffinetly had a long mysterios life, and I'd wish I had the oppurtunity to watch the movie.