Yeah, some of the pet shops in my town keep 1 male Betta in a tank, regardless of the tankmates, and they don't seem very agressive towards other fish.

But yeah, the gouramis are getting along better then I had thought, so that's really nice. I think I may add in a 3rd Pearl to my list, since I read they actually enjoy each others company, whereas the Opalines/Gold are more agressive.

I actually came across a post of yours where you mentioned the tank that you added barbs to, most sites are saying that if you keep a large group (6 ) that they'll keep to themselves more.