a fan moving air should be fine.. the other this is that you can build a makeshift pet door to block stuff off. If you have ANY pieces left over from building one of those condos, you can zip tie them together to block of the door (we did that for the kitchen)
The first time I bonded them was in the bathtub.. no door needed!
I just used my x-pen and put them both in there.. and it was easy to move around- that’s also what they use at the shelter we got patina from.
It will be easier to bond post neuter- I have a horrible time getting my male to stop mounting my female- and he was fixed! You should wait some time after his neutered before you start.
Also– the stunt bunny worked wonders for me- it let both of my bunnies really get their aggression out on this stuffed rabbit, so when they met it was as bad. You should do a search for “Patina and Fujoe Bonding Journal” – you can see what I went through, and letting you know it took me a month of frustration– but it totally paid off. good luck and congrats!