Thanks for rescuing these two bunnies – they sound like they got lucky!
It’s great that you got them both spayed – that’s the first step to bonding!
Dividing the room in half is a good plan, but make sure they can’t touch each other, as bunnies have been known to fight and bite each other through bars. My own little Atlas got a nasty bite on the ear from Luna through cage bars.
Peeing and pooping along the fence is normal – it’s territory marking, so you’ll often find bunnies peeing and pooping along the edge of dividers to mark space as theirs.
I would say the next step for you is to start swapping them between halves of the room, so neither sees either half as ‘her’ territory, and so they get used to each others scents being in the area where they live. They might well be angry at the beginning. Do this for about a month. Hopefully, by the end of a month, they won’t care about the swapping anymore, and you’ll start to see them do things like lie alongside each other through the fence.
At that point, you can try introducing them for a short amount of time in a neutral space
I’m happy to help with that part later 