[@Mercenary Lord]
On the villain...

Feel free to submit a CS. I personally am fine with two characters, though I'd have to discuss with Reg on more than that.

Weaknesses differ, in all honesty. They're unique to the person, and even if you share a thing with another, they're going to function differently.

So while Phantom has to drink it, another person might not be able to even smell it, but could drink it. And another might not be able to even be near it.

Others are more... Concepts than physical things. It's really tied into your history, generally something you had a negative action with, or it can seem random. Maybe ironic with your peers, like Stark. 

Does that help?