You’re not crazy at all! I think most of us would want to save that little girl bunny too. It sounds like she really deserves a good home and especially if she’s had a difficult life before you, that makes it harder to wait it out. It’s good that you haven’t met her yet though- that gives you some distance to consider the practicalities.
I think most bunnies are happiest with a companion- it’s just the timing, and making sure Cady agrees that this bunny is “the one”. I let my male rabbit, BunBun, pick his wife, Nelli, and it’s worked out wonderfully. Because of this, I’m quite biased toward bunny dating rather than us picking out the new arrival. But I know it is possible for rabbits to bond even if they didn’t “choose” each other, like Monkeybun stated. It’s probably more likely that the bonding will be easier if they meet first and like each other, though.
One thing is that male bunnies can be pretty obnoxious with the humping thing before they’re neutered. BunBun had been fixed for 2 weeks when he met Nelli and he was still pretty hormonal. It was awful- during bunny dating, he jumped on top of every lady bun he met, even ripping a chunk of fur out of one of them in his enthusiasm. His humping lasted about a week, then he calmed down. But I can’t imagine how bad it would’ve been when he was stil intact! So it would be hard to tell just how well they get along until Cady is neutered.
I think that if the girl bunny can live at the foster home until Cady has been fixed for a couple weeks, that would be ideal. If it’s more of an urgent situation (and I know you said adoptable bunnies can be scarce around your way) then I would take her home and keep them seperate til Cady’s neutered/healed. Then hopefully they will get along- if not, plenty of people have 2 or more rabbits that aren’t bonded. Good luck!!! \
PS. Cady is adorable- he looks so surprised and full of mischief!