You sound like you have what you need, my only suggestion is get rid of the plecosaurus poopicus maximus, because he's not gonna be happy, and though they are very peaceful when they are in the right habitat, when they feel crowded they will lash out at other bottom feeders- my 7 inch pleco ate a couple of my otos last night. I moved my pleco to a 55g plastic tub. I'm probably gonna trade him in for store credit at my
lfs, considering my mom is sick of plecos. If you get a chance to show off your betta we'd all love to see him!!