Cheria:

I'm pretty much cool with him using any of those on her. Just sans actual mind breakage since that would be kind of hard to recover from.

Lelouch:

He'd be able to notice influence when he sees it since he has a similar weapon/skillset. So he'd be on guard about that pretty quickly if it comes up! I'm pretty much good for anything, though Lelouch will try to Geass him if it seems like he's got too much power. Which means go fill out my permissions again with Aoba. >:(