I’m having a bit of trouble following your post. If I read it correctly you have 2 pairs, a m-f and a m-m, and all the boys are neutered? And then another female that you want to add into a trio? Is your question about what to do with the m-f pair?
If your m-f pair is already bonded and the M is already neutered, I think you could try just keeping them together the whole time, as long as you are able to monitor them closely. If you notice signs of trouble you should separate, so you should be prepared for that possibility with extra cages etc. You will need to restrict her space, even though she will be unhappy about it. So you’ll either need to get a hutch for her, a large dog crate, or a secure pen that she can’t jump out of. Perhaps something with a secure roof will prevent her from trying to jump out? Maybe you could make a temporary NIC cube cage?
.
.
.
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.