Threadjacking: As long as it's not locked, go ahead!
Backtagging: Always.
Attacking: Go ahead, but Lion will defense himself -- possibly with angels, depending.
Hurting: As long as it's nothing too severe, go right ahead. Fights happen, people get hurt.
Severely Hurting: Ask me. In general, this is no, but I might have a use for it.
Maiming: No. Sorry, but he needs all his body parts intact.
Killing: Ask me on this. It's a very severe thing, but could be played properly.
Hugging: Sure! Lion loves affection, even from strangers.
Kissing: Go ahead, but on the lips will likely get you shoved away by a flustered Lion.
Romancing: Yes, if you want to try. There's no guarantee that he'll fall for your character, however.
Fourth Walling: Sure! He'll probably have no idea what you're talking about, though.