I almost thought of making Rhett a bad guy in my LBT finale, but he doesn't have as much reason to as Chomper's rivals for the girl Chomper likes. In their case, they stand to gain leadership of a Sharptooth pack (which they'd like to boss others around) and as Chomper is, well, different, they feel that it would be shameful if, by falling in love with the leader's daughter, he'd get the leadership position and so seek to do him harm.
However, Rhett has only one reason to go bad, he might want Littlefoot out of the way so that he can get Ali. But siding with such a bad guy as Gallim seems too low for Rhett.
I thought Loofah and Doofah were cute.
I actually am neutral toward Mo as I love him as he's so cute and all, but his constant optimism, which beats Ruby's even, plus his spitting water at everyone, makes him come across as kind of annoying. His voice though, is adorable and second only to Guido's and perhaps Ruby's.