Welcome to AA!
You'll be hard pressed to grow many plants under that light. Mosses, java fern, and anubias would probably survive, but I doubt they'd thrive unless you raised them up near the light on rock or wood.
The best bang for your buck will be a shop light from your local home improvement store. You can probably get one with halfway decent reflectors and a pair of daylight spectrum 40W T8 bulbs for $50 or less.
Aerating the tank will actually off-gas CO2
, which plants need.
A 50g HOB
, 405, and FX5 on a 55g? That's probably crossing the line into the category of ridiculous overfiltering. The FX5 would be plenty. When you're ready to set up more tanks, feel free to take a filter off your 55g. In fact, pull the HOB
now. The agitation also off-gases CO2