Hi Jenn!
Welcome to the Gang of Five! I hope that you'll enjoy this place as much as I do
You are certainly right with what you write about Bron's herd. We get a very distinct clue that they are no wanderers, when Bron says: "I can't wait to introduce you to the others
back home". That sure doesn't sound like they are a migrating herd. It may also weaken my reproach of Bron being irresponsible for leaving the herd to head for the place where the solar eclipse takes place. However, it also raises the question why they depend on him at all. If they are in a place save enough to be left behind there by Bron (a place where they have stayed long enough to call it home), what for do they need a leader anyway? The Great Valley doesn't have one leader either, and there is not a one of the dinosaurs in the Great Valley that is so important for the Valley that his or her departure would cause any harm.
I almost envy you for being able to judge the character appart from the movies content. When I watched Lion King 3 I found it quite funny, though I was sure that the movie must have made devoted fans of Lion King hit the roof. It was just that though I really like Lion King very much, my affection for it is not nearly as strong as it is with the land before time, so I was able to take the discrepancies there with a smile. I can't say the same about LBT 10.
As for Bron's character, we don't learn very much about him. We mainly get to see him in such special situations like when he is explaining Littlefoot why he hasn't been around, when he is fighting the sharptooth, or during the solar eclipse. The only every day like situations with him are shown during the song "Me and my Dad", and the conclusions one could draw from these scenes were limited.
Maybe the most informative scenes about Bron were those that dealt with Shorty. I may be mistaken, but I don't have the impression that he really "adopted" Shorty until very late in the movie. Until the end Shorty doesn't make the impression like he had someone to care for him, or to educate him. Also you will see in the flashback that it is not like Bron was picking up Shorty and the others after he found them, but it was rather them following him as he was walking away. If Bron had really cared for Shorty I doubt that Shorty would have developed the way we got to know him before Littlefoot's "talk among brothers" with him.
By the way Jenn, do I know you from another board or elsewhere already?