Yea, I hear you. So it's more about space and aggression than biological capacity.
Since none of my fishes are particularly dominant, I guess that's why I'm feeling okay.
The clowns nip at each other more than they do at the other fishes (but they're definitely paired). They leave the other fishes alone, including when the other fishes are near their nesting area. The only thing they really aggressively nip at in the tank is me when I'm working in the tank
My wife now has the job of chasing the male clown away with my ghetto two-glued-together-chopsticks extra long probe while I'm gluing things down or rearranging things.
After you brought up the tank size for the wrasses I had a mini crisis over whether it's reasonable that I have one, let alone potentially 3 fairy wrasses in my tank. I still think they have a great time, and will likely not outgrow the tank. And I hate to say "by the time they outgrow it, I'll have a bigger tank" because that's what everyone says, but A. it's probably true, and B. I don't think they'll out grow it either.