I'd stick with the Dwarf Gouramis, esp if it is your folks who are paying for the tank. I also like the Kuhlie loach idea as the bottom dweller. Why not 4 or 5 checker barbs, a really awesome fish, very hardy, subtle but distinct coloring so you can tell which are males and females (males have a reddish dorsal fin).
It always pays to keep those who are giving you the funding happy...
Val