Orange Dwarf Mexican Crayfish - Cambarellus patzcuarensis is a fun scavenger.
Not over feeding to begin with is a good thing.
Check out the getting Started article in my signature link below, it can give you some great basics and key information for healthy and happy fish keeping.
I think one Mystery snail, they usually clean up super well, and start out smaller when you buy them, and maybe a Nerite after the tank stabilizes and or gets some algae/ biofilm for it to eat.
Check out if any of your lfs
have Green Neons, they are pretty and sometimes the Neon Tetras are a little weak. Worth at least checking them out.
Have you considered some Dwarf Corys? You can have a nice bunch of them like 8 and they are so small they are more like 3 bigger ones.
There are other smallish cories you might consider as well.