We know even less about Rhett. Maybe he was a habitual lier, or maybe, like I mentioned above, maybe she talked about Littlefoot when they first met and he felt he had to make up stories to seem good enough to be friends with her.
I didn't have an idealized version of her, one of the benefits of being old, it's just the Ali in the episode seemed a bit less experienced then the one in the movie in certain ways. Believing someone of her size could make a mountain with their tail is a bit much.
As for attraction, it is likely of the friendship type. Someone of around your age that you travel with, unlike others who you may meet but will only be with briefly.
If there is a season 2 I wonder how she'll be treated in that one, and Rhett too for that matter, if he does appear.