No idea about the peeing/pooing in the bathroom thing, though it sounds pretty funny (maybe because I’m not the one that has to clean it up LOL).

With regards to the biting, does she nip you, as in puts her teeth on your skin but doesn’t actually bite through, just grazes your skin? If that’s what she’s doing, then they’re “love bites” meant to show affection, unless you’re doing something she doesn’t like or are in her way, in which they can be a sign to stop or get out of her way but in a playful way.

a bathroom often triggers toileting behavior in animals due to the scent present. It will get better when she is spayed and you can littertrain her

Do you have two rabbits that both are allowed in the bathroom at alternating times? If so, that could also trigger a marking behavior.

I asked the same thing the other day. Huckleberry does this too! And she is 1 year old and spayed. She still does it! When we scoot her out she does the same thing and forces just one more out if she can, then shakes her tail and head and binkies off. She is giggling at me, I swear! She knows she is being naughty and she enjoys it. What can you do though? They are too darn cute, they get away with murder. I was told that it was territorial. I can imagine that, since we are doing the same thing in there and she believes that WE are HER tenants, not that she is our pet. Good luck with it. Maybe a litter pan in there might help? Otherwise, just try to keep the door shut or put a baby gate up. Its a pain but its better than stepping in a fresh puddle of pee in the middle of the night.

I’m also currently experiencing some bathroom marking from my spayed Doe. She’s a notorious marker but the bathroom has never been a problem. Even though it was the area I used when first bonding her to Rumball.
My bathroom is opposite my bedroom where I’m keeping a young 7-8wk old rabbit and I have a little marking outside the door but mostly in the bathroom. I thought that was odd.