However, Katniss is initially fighting for her own family within the status quo of her society, while Jake et al are fighting to prevent a negative change in theirs. That makes for significant differences in the character arcs.

True! And yes, I agree, Animorphs still wins as Most Depressing Series Ending Ever, lol! ;)

I suppose they are in the same subgenre, even though Animorphs was meant to be for a younger age group initially...(although it had a lot of gore still, now that I think about it...)