IMO, that is a slightly overstocked tank and I see alot of possible future aggression problems. I'd be worried that the bala hasn't grown any, it would likely be a sign that it has become stunted already.
Also, watch the gouramies, dwarf gouramies are extremely aggressive towards each other once they have territories established and the max you should really do in a tank that size is 2 because the third will be stuck in the middle of the two territories and beaten alot. Seeing as they get 14-16 inches and are a schooling fish, they really need a big tank. Why are all the neat fish so big?
Another possible aggression is that from your description, it makes it look like you have 2 albino bristlenose plecos or white gibbies and the BN are aggressive to members of their own kind and gender, but if you have a female and a male there is a good chance that you will soon be overstocked, I knew someone with over 300 ABN in her 75 gallon tank because they wouldn't stop breeding and she couldn't catch them fast enough. Gibbies, or Sailfin plecos get mostrously huge, about 18-24 inches and won't turn down the possibility of a sleeping fish for a midnight snack.
Happy to see you upped your neon school, 14 is a really nice number and I bet they prefer it alot more!