Hee, okay! Well Lena isn't cruel so she'd need a good reason to silence someone. I believe she's only done it twice: once to stop her boyfriend from telling her family she was running away, and once when a guy was making fun of her boyfriend's great aunt who was now a "vegetable." So once for her own dire needs and once to ease her boyfriend's pain. If we can think up a situation where Susan needs to be silenced for the greater good or something, that could be fun!

Hmm, well objects move either because she wants them to (so with her mind) or because she gets emotional and can't control her powers (which I guess would fall under just magic). It sounds like this sword would probably be immune and really, that would fascinate her.