You can use Neosporin on rabbits. It should be the plain kind, not the kind with pain relievers added. I don’t think you should get that in her eye, though. Hopefully you could put a small amount on the cut and she wouldn’t rub it into her eye. If you are worried about it getting in her eye, maybe you should wait and call the vet in the morning and get his/her advice.
It really is not safe to put the new bunny with your other two. Hopefully your husband won’t do that again. Even more serious injuries could occur. You will need to keep the new bunny separate, until she has had surgery, recuperated, and you can start the bonding process. Make sure that your two rabbits are not able to bite her nose or ears or any part of her through cage bars. If they are in the same room with her, you may need to double up on pens, to have a buffer between her and your two.
Thank you for taking in the bunny that was likely thrown out by someone.