I agree you found a good LFS. I'd keep going there and respect their knowledge.
I only wish my LFS ws that smart. They told me my 10g community could support in upward of 25 fish or so. Sorry, but I don't want to run my aquariums like a pet shop with a million fish per gallon of water.
I'd say lose the Bala and you could probably run a school of 10 neon or cardinal tetra. Of course tank maintance is important.
I have a 10g. with 2 peppered cory, 2 dwarf gourami, and 4 zebra danios. i keep after the tank and it works fine, but I'm still not far over the 1" fish p/ gal rule. I'd listen to your LFS!!