Your stocking idea is great, I agree with everyone on adding a few more to the danios and tetras.. I also would make a suggestion for your tank, instead of apple snails (which may harm any plant plans you have in the future, try a handful of amano shrimp, very peaceful with other said fish, and they clean up the tank all the time.
One last thing... I saw at petco the genetically altared glofish.. They are Zebra Danios that have been gene spliced. The thing about them is, now they are a true strain of fish that can be bred, with the same bright glowing colors as their parents.
They really are amazing looking fish.. You can get them in green, red and orange... two of each would look really cool in your tank, and add a lot of color...
http://www.glofish.com/