Well, I still haven't gotten around to seeing the 1st film (college workload is catching up to me since I started donating my free time to the GOF) but until then I just want to make one more comment.
I wonder to which degree Cera, Ducky, Petrie, and Spike would actually agree on the notion of Littlefoot as their "leader". I guess they might be rather surprised at this point of view (outraged in case of Cera) and would consider Littlefoot a friend rather than a leader (two points which need not exclude each other, but I doubt the others would consider themselves on a widely different eye-level when talking to Littlefoot).
This statement actually reinforces my thesis. In a situation where your fellow group members don't feel like or want to be led by anyone, a true leader has to be able to put his hubris aside and act as more of a 'hidden' leader, as in, be a leader that leads, but without the others really knowing it. If Littlefoot had just stepped up and said, "Well, we should do this because I'm the leader and I said so," the others (probably starting with Cera, like you said) would quickly mutiny. By not calling attention to the fact that he was calling all the shots, and just silently allowing the others to subconsciously fall in line behind him (which most individuals will do due to the Follower Effect), Littlefoot was able to lead his friends and still decide the right courses of action without inflaming an already tenuous situation.