What type of plants are you trying to keep? A nano cube uses a wet/dry filter setup, so keeping co2 levels up for some higher needs plants could prove very challenging. On top of that, the fish list you put together is way too much for that size tank. 2-3 discus would be ok (general rule of thumb is 10 gallons per discus), but they really do better in groups of 5+. I would rule them out for this setup. Out of the others you have listed, I would do 10-15 shrimp, 5-7 rasboras, 10-15 cardinals, and 5 cories. Or if you want to have a showpiece fish, go with a trio of rams, 5-7 rasboras and 5-7 cardinals. HTH.
Thanks guys. I'm actually not going to do this setup, but a friend of mine has already done it and he hasn't had any problems except he does seem to get ich and have to treat the tank twice now. His tank is really beautiful plant wise, but it does look like too many fish. I was wondering if that many fish would cause more stress on the fish leaving them open for infection easier? Trying to figure out why he could keep getting ich. Can most fish fight off minimal non-visible signs of ich input from new fish stock in a healthy less populated environment?
He wants to give of planted and go back to reef. He makes some amazing reef tanks, but I don't want him to. My point to him was... would you put that many fish in a reef tank? Probably not that good of a point, but close enough.