Hi Joe!
You have some cool fish, but I have a few suggestions for you!
Eventually you should probably plan on a larger tank for the silver dollars, those guys are skittish and man can they fly around the tank! They like to be in groups of 5 or more
Cories should also be kept in groups of six or more
Rainbows I believe also should have a larger tank and be grouped 5 or more.
Your tank may get a little crowded a some of them get bigger.
Good luck!