The ones that he has listed I'm pretty sure are Dwarf Gouramis. No other Gourami really goes by the name 'Frost Blue' or 'Flame Red'.
They only get to be about 2 inches give or take.
As for what fish NOT to stock it with:
Barbs, they nip
Betta, Anabatoids have this thing against each other...
Pleco, the get too large and you woundnt want to cramp him.
Tetras and Danios are fine.. but the best way to find this out is to just do a wee bit of research. When a fish catches your eye, take down it's scientific name and Google the Hell out of it.
Also, are your two Gouramis males? If they are.. how are they getting along?