I: She can attack him, but he will attack back and he's a powerhouse. So basically I'd say probably a good idea for us to chat before anything because Leonhardt comes with enough warnings of his own if attacked. Probably won't agree to killing though for some time.

II: I'd consider it!

a) Sure, but it will depend on if she's seeing him or one of his shadows. The shadows likely have no aura since they aren't living creatures. As far as Leonhardt's, not sure about how auras work in Buffyverse, and he's a weirdo as it is. If you can give me a basic rundown of how it works in their canon, I'd be happy to give more details.

b) I'd not be against it, but I personally see him having some mental barriers that would make it harder for her.

c) Gonna say no to this.

d) See answer to b. He's definitely familiar with hypnosis and how it works, so he'd be able to defend against it to some degree.