What type of pleco is it?
Have you got wood for the pleco?
After the botias that would be more than enough fish IMO
if your looking for bottom feeders then instead of the botias you could get a small school of pygmy corys these grow up to 0.75 inches where as the botias have been known to grow up to 5 inches and im not sure whether they may outgrow your tank.
Do you get plants and hiding places for the female bettas and the loaches? they are going to need them as you may know the females can be just as aggressive with each other as the males. Some tall plants and midground plants would be great IMO, the tall plants will make the females less stressed for when they go to the surface and the lower plants can then act as a place to hide. I would also recommend some caves, you can use stones or ceramic pots, these are what most people including myself like to use as they aren't expensive
just remember to cover the little hole so that no fish get stuck, which surprisingly does happen