permissions
OUT OF CHARACTER
backtagging: Yes. I rarely drop threads without saying something, and will backtag pretty much forever. You don't even need to ask.
threadhopping/threadjacking: Depends, really. I'm generally not fond at having people carry on threads with each other on posts directly concerning my character that are made by me. However, if it's a mingle of some sort, or I put a threadjacking free-for-all note on the post, then go right ahead! Conversely, if you want to threadjack me on someone else's post, I'd just ask that you make sure the OP is cool with it first.
fourthwalling: Sorry, no. This has made me really uncomfortable in the past.
canon puncture: I'm going to say no, again.
offensive subjects: Depends. If you're worried something will offend me, drop me a note on my HMD or via private message and we can discuss it.
IN CHARACTER
hugging: Judith hugging is an odd image to me, but sure, why not.
kissing: Go ahead! She'll probably kiss back nine times out of ten.
flirting: See above, only replace kissing with flirting.
shipping: I am generally up for most things, and never say no to discussing it. However, most of the time, the characters decide. If the chemistry and CR isn't there, then it's unlikely.
fighting: Go right ahead.
injury: Ask me first, I'm generally agreeable but like to plot things out ahead of time.
death: Again, I am always up for discussing it. It's not something I'd want to do lightly, though.