plants always benefit from co2. pointless to have high light and no co2, cant say exactly why, brains turned to mush with the current meds.
and i suck at IDing plants! so im not much help there
get a couple otos for algae clean up, and ask the store if they wanna throw you some snails. i know some people hate them, but i think their the best cleanup crew (and free is always nice!) out there, and if you get overpopulated you know its cause your overfeeding and you can just go smash them and fish will clean them up, or a population may not be able to keep due to the yoyo loaches