Like Blue eyes said, that vet may be a risk even to have your male neutered. Try looking on the rabbit vet list link below to see if there might be another more experienced rabbit vet near you that will do the spay(and neuter). But getting an already altered fully mature rabbit that you can let your boy bun have a date with is the preferred and easiest route to go if you can find any at a rescue or shelter.
https://rabbit.org/vet-listings/
But if you decide to go with this baby female, and if you still end up not being able to get her spayed, then just be aware that if she is terribly hormonal as she matures(usually around 4 months old), this could affect their bond. So if you start to see her pestering him and he starts showing too much annoyance, it could escalate into a real fight which you want to completely avoid occurring. So if he starts getting too annoyed with her then you might have to separate them and just have to do some traveling to get to a good rabbit vet to do her spay, which would also remove the uterine cancer risk for her. Though keep in mind that getting her spayed doesn't guarantee they will bond either. Some rabbits just don't like each other and you can only know if a bond will work when a rabbit is fully matured with their adult personality.
Other than all that, to bond just go through the normal bonding process at least 4 weeks post neuter(though sometimes waiting 6-8 weeks is necessary due to hormones, especially if she is older than 12 weeks as he could still have some viable sperm and get her pregnant). There is a fast and slow method, as well as deciding on a small(2x2 or 3x3) or larger bonding space. The bathroom/bathtub can work, or using a playpen to set up a neutral bonding area is also a common method to use. Depending on the rabbits involved, one method and/or one space may work better than an other. I think I would decide which to use based on how they react living next to each other while he is recovering from his neuter. If they seem really interested in each other and like being next to each other, then I would probably opt for the fast method in a small space. If he reacts aggressively with her being next to his area and continues to show dislike or disinterest in her, then I would be inclined to do the slow method, being very cautious at introduction to make sure he doesn't try and attack her. You also need to be careful because she will be younger and smaller than him, and more vulnerable.
https://www.cottontails-rescue.org.uk/information/bonding-bunnies/
Also if when you get her and put her in her area next to him and he reacts negatively towards her and she acts scared of him and doesn't calm down in a few hours, I would strongly consider keeping her in a separate part of the house away from him, for a few weeks for her to settle in, or maybe even the whole 4 weeks of his post recovery. Reason being is that if she is scared and being in a new home, this can cause an extreme amount of stress for her, and this can affect her health. Particularly with newly weaned babies who are extremely susceptible to developing dangerous digestive diseases at that age. And stress can be a triggering factor.
If my presence seemed to make her feel safer, I would spend a lot of time with her that first day to help her settle in. If me being around seemed to make her act more nervous and I couldn't put her next to my other bun cause it also scared her, then I would put her in a quiet part of the house, partially cover the cage with a sheet so she could feel more secure, and mostly leave her alone to settle in while checking on her occasionally to make sure she is ok and eating. Monitor her food and water levels closely to make sure she is eating and drinking fine. If you have a water bottle, I would also offer a water dish as rabbits tend to drink better from them.
Offer free fed good quality(no mold, no noxious weeds) grass hay(timothy, orchard, etc) at all times, as this will promote good digestive function which can help prevent digestive illness from setting in. And make sure to get 2 weeks worth of transition feed from the person you are getting her from, or at least get the exact brand and type of pellets that she is used to. Then if you want to change pellets give her a few days being in your home, then gradually over the next 2-4 weeks, transition her onto the new pellets by gradually decreasing the old while increasing the new. I would also not feed any sugary/starchy/high carb foods, and hold off on introducing any veggies/leafy greens until she is 12 weeks old. Unless she is used to eating certain ones from birth with the mom rabbit, then she should be safe continuing to get those same veggies/greens.
I would also recommend seeing if the breeder will keep her until 8 weeks old, preferably with her mom and/or siblings if safely possible. Reason being is that baby rabbits really shouldn't be leaving home until 8 weeks because this promotes better health with them and less of a chance of digestive illnesses occurring. And if the mom hasn't kicked them out of her space, then it's best they stay with mom until 8 weeks old. It is also a law in some states that babies have to be 8 weeks old to be sold, but may not be in yours. It's just better for the baby, so that's what I would recommend.
