I just read through your previous posts, and I'll quote some of your comments here:
"There was head to head fighting constantly. If we did not separate them they would have really hurt each other."
"they locked teeth we could not get them apart for a few seconds. My female Boo had a head tilt for twenty minutes afterwards....Every bonding session has been fighting."
"The new rabbit has not experienced bonding with another rabbit and probably had minimal human contact."
Also, I was very surprised to find out that you have only had this new bunny for
5 weeks and started bonding after only 2 weeks, and that your existing bunny had only lost her male bondmate a month before bringing in the new bunny.
So your bunny was stressed from losing her mate, is possibly still grieving (you don't mention how hard she took the loss), the new bunny has little experience with humans and new rabbits, and is in a brand new place, doesn't even know if this place is temporary like the shelter, the smell of the previous male is probably still pretty fresh all over the house, and you're trying the hardest bond (female-female), and between dwarf bunnies, who are often more high-strung and territorial. Try to put yourself in these bunnies' paws and see why you might be having trouble bonding them
Blue Eyes has given some good advice, and also gave you the names of two good rescues right in your backyard. I would contact them to see if you could swap your new bunny for a more compatible one. I know that's difficult to do, and I've never been able to do it myself, but it's easier to do at 5 weeks than later on down the road.
I would definitely stop the bonding efforts for a month, at a minimum. If you continue trying to bond them now despite all this serious fighting, you risk even more dangerous injury, or traumatizing both bunnies to the point where they will have difficulty bonding with anyone.
If you do want to try to keep both, I would recommend the following:
1. A thorough deep clean of the whole home to get rid of any smells of the male. You will have to ask yourself if your existing bunny still takes comfort in having those smells around (as some of mine have). Maybe keep a few items with his smell on them just in her cage.
2. Checking whether the new bunny has indeed been spayed. Did the Humane Society do it, is there a Spay Certificate, is there a tattoo or scar, or did the people who surrendered her just say she was?
3. Focusing on socializing the new bunny with her new humans and in her new space until she seems thoroughly comfortable with and trusting of both, with NO bonding sessions with the other bunny in the meantime. Her fear and stress level has got to be lowered. This may take weeks, or months. Building trust is crucial, and the sessions you're doing are working against that.
4. Read the bonding document at this link and follow their advice:
Bonding Rabbits: A How to from Georgia HRS | House Rabbit Society. This is the best guide I have ever found, from a rescue near me that does have a bonding service and has bonded hundreds of rabbits. They don't believe in stress bonding (which is what you have been trying).
5. Ask yourself what you meant when you said "My husband said maybe we just keep both and keep them separate at all times
but I really want the bond." [emphasis added]. Is it just for convenience (being able to have one runtime instead of two), or do you want to see the grooming/snuggling/lovebugs type of bond? If you never got a bond, would you be disappointed and not enjoy the bunnies as much? What does "the bond" mean to you? The answer to those questions may help guide you as to what to do. Also ask, why the hurry to get it.
(Any questions above are just for you to ask, I'm not asking for an answer here)
Now, some of my experience:
I've bonded two dwarf bunnies before (several times), but always male and female, and still none were quick bonds. I distinctly remember my first ever bunny, a female dwarf, after she lost her first husbun of 6 years. I brought in a baby boy dwarf, thinking he would not be threatening to her and her maternal instincts would kick in and she would immediately groom him. Uh, no. She attacked him. They eventually ended up snuggly, but it took a while, especially since I started them off on the wrong foot!
The only female-female bond I had was that same female dwarf who lost her third male partner many years later and then became closely bonded to my
12-pound single girl (!) that she had previously attacked through the fence. They were only bonded for 1-1/2 years, since the dwarf girl died at almost 14 years old, but they were inseparable. Watching a 2-lb and 12-lb bunny snuggle is something! But they had both been living with us for years, and in the same room, so were very comfortable and familiar with each other and their surroundings.
When the dwarf girl died, the big girl grieved so badly we thought we'd lose her, so I went searching for a new partner. I found a male lookalike to her former partner, thinking that would make it easier to bond them. Not so. I think it just confused her. They never did bond, though in retrospect, another 1/2 year to a year might have done it, since their fighting was mostly pulling fur and they did loads of mirroring. But the dwarf boy was getting depressed, so I got him a new dwarf girl of his own. That was a pretty quick bond (only a month or two).
By the way, the two times the big girl and new dwarf girl got out together by accident, it was a trip to the vet for the dwarf girl with a deep wound each time (one narrowly missed the jugular). When two bunnies don't like each other, this is the risk you take even if you keep them separate, or if you have a forced bond.
I had two young (unneutered) brothers who were bonded while at the shelter, but we took them home 2 weeks apart, which broke their bond. They fought through fences for 9 years and wouldn't rebond. The one that knew how to approach females had 2 female partners over those years (one of them my lonely big girl). I tried bonding the single brother to another rescue male who desperately wanted a friend (any friend). I gave up because the single brother started becoming withdrawn and losing weight and changing his personality due to my trying to bond him with someone he didn't want to be with, even though the other bunny groomed him eagerly every time they were together.
After 9 years, when the two brothers were old and a bit arthritic, and both single again, I tried bonding them one last time. Within a few weeks they became inseparable, grooming and snuggling constantly. It was very rewarding, though they only had 8 months of that before one died and the other followed the next year. So it can potentially be done -- if you have enough time!
That friendly bunny that always wanted a partner and has groomed everyone I've put him with (and always been rejected) is now 8 and still single. I've been trying to bond him with a larger female that I rescued 5 years ago because she was unadoptable (too aggressive!). She has come a long way -- I no longer fear that she will kill him -- but last night he groomed her flank and then snuggled up next to her right before we ended a territory swap, and she reached around to nip his nose. She might have done more if I hadn't had my hand on her shoulders. He was not hurt physically, but visibly hurt at the rejection. I am considering looking for someone who will love him back, but that would get me back to 3 rabbits (or more), when I was so happy to be down to 2 from 6 at one time.
Note that I ended up with 6 rabbits mostly due to trying to find partners for existing ones, and not wanting to (or being able to) take any of them back. A cautionary tale!