Shrimp and Ramshorn snails and 6 Chilis, there are a few other possibilities. Shrimp would like some Java Moss/low light plants, and the light could go on a timer.
And don't over feed them. The micro fish might need you to use Micro Bites from Hikari and grate them together with your fingers to make them even smaller. They have tiny mouths.
I wouldn't use flakes in a tank that small either. Can too easily cause ammonia spikes.
For the moss, not really anything to take care of just keep it out of the filter intake and get a pre-filter sponge to cover it so the shrimp don't go into the intake and turn into shrimp puree.