Excellent topic, OP.
This can be hard on anyone, especially if you're a big time cat lover. It feels like re-homing your children.
The best answer is to do what you believe is best for the animal.
I'm going through something similar (as mentioned in a different post). I have a cat that's nearly a year old, and when I was looking for another kitten for him to have as a companion, I was talked into taking two (they're siblings). I love them to death, and they provide a LOT of company, but my neighbors aren't quite so sympathetic. They chase each other around sometimes at night, and since I live above my neighbors, they can hear them running around and jumping off furniture.
I've been hunting for ways to try and keep them calm (unfortunately, I don't get home until 1am from work, so I can't play with them before bed without creating a ruckus), but I want to do it in a way that works for everyone including the cats. I don't consider crating to be inhumane unless it's for hours upon hours on end, which would be what would have to happen.
I too have considered re-homing for both their benefit and the neighbors', but I'm saving it as a last resort.
Like I said, OP, do what you think is best for your animals