From my experience keeping Rainbow fish for many years, you shouldn’t have any problems.I've had Rainbows in large schools and some just a pair only. I’ve never noticed any difference in coloration, behavior, or aggression based on the size of the group.If the fish are well fed in a healthy tank, they will show brilliant color. I don’t care if you have one or a dozen. I’ve also never had any aggression or nipping between Rainbows, other than the normal males challenging each other and flashing. This is normal Rainbow behavior, and is neat to watch.Personally, I prefer having several different species, so you have a variety of colors cruising around the tank. Rainbow fish don’t really school anyway, it’s more like hang around in the same vicinity as each other.If you’re interested, here’s a vid of my Rainbow Community Tank. You’ll see each of the species you mentioned.[YT]jDyYWPlHeMg[/YT]