I realized early on when Nyu was digging in the sand that she was after a new shell

That's very observant. It was only this rewatch that I realized that is what she was up too. I'd always assumed she was acting weird for basically no reason.

but that she couldn’t figure out how to change her own clothes.

Quite true, but then what excuse would they have for fanservice. lol

that it was satisfying to see him defeated.

That is quite the highlight of this episode when he has a chat with Lucy.

Lucy who tends to have a homicidal streak

I agree with what you've said here about both Lucy & Nyu. Lucy is just too much like a hand grenade about to blow, to be real comfortable around.