hi! here are some of my favorite nano fish
- gobies
- cardinalfish
- blennies
- basslets
- peaceful damsels
- chromis
- pink streak or possum wrasse
- dartfish
- orchid dottyback
all of those are usually peaceful and any of them should be good in your tank :) you could probably have 2 or 3 more fish depending on what you choose and your filtration
as for inverts, i'd recommend a more varied clean up crew. i would get some astrea or trochus snails to clean your glass, nassarius snails or a conch for your sandbed, and maybe an urchin for general algae clean up.
and for corals it depends. what types of corals do you want to keep? do you want to have to dose? do you want easy corals?