1. size-wise the fish are fine. You'll be above recomended capacity for that size tank (close to 1"/gal
with adult fish).
strip light will be fine, all it's needed for in this situation is to see your fish. Whatever powerheads you go with, try for turning the tank over at least 10x an hour.
Skimmers won't increase capacity really, just make water conditions better. It may allow you to fudge a bit on the bio-load, but if you ever have a power failure that increase bioload could wipe the entire tank relatively quickly.