The twins (or whatever they were) were always top tier for child characters. The voice acting wasn’t the greatest with them sounding a bit whiny, but they were solid.

You gotta figure, Lion-O was “one of them” before the trip… assuming they’re siblings (not sure if they said), Lion-O could have been a potential mate for Kit, if they were all allowed to grow up together. So with him being aged up all of a sudden, it’s like he’s still their bro/friend/playmate/peer/whatever but now he’s kind of like their king (“Lord of the ThunderCats”) they wanna help him get better. And of course their thing is underhanded/sneaky tactics and devices (kinda like Q in James Bond), they always have a trick up their sleeves.