Same-sex bonds are always a little trickier and have some bumps in the road on occasion. Your trio of females is always going to have these flare-ups, I imagine. If you feel like she might be happier bonding with your solo rabbit now, I would trust your instinct.
If you're ready to start bonding them, I see no reason not to. However, I would be prepared to separate her from the rest of the trio permanently and house her separately during the bonding process. Taking one rabbit out of a trio bond and having them come back after a bonding session smelling like "some weird dude we don't know" could potentially upset the trio's bond. You need to watch for this when you return her to her cage and be prepared to deal with it if it happens. It doesn't always - I am trio bonding now with a M/F pair and a solo female, Nala. There have been times that I did a one-on-one session between Nala and one member of the pair. When reunited in their cage, the pair was okay. However, I feel like this might not be the case when the returning rabbit is the one the other two already like to bully sometimes. If you don't separate the trio when you first start the new bonding, I would at least separate them when things start to get serious (think: the rabbit version of getting engaged - it's almost time to move in).
Anyway, you should be able to see pretty quickly if for some reason your widower bunny isn't receptive to the idea of a new bond so soon... But I think the odds of that being the case are very small.
.
