for the mean time, I think I might remove a piece of wood and replace it with a couple of small tight caves, more water, more hiding places. I'd also overfiltrate that tank to the max, it's going to be very messy and take care of your params, you'll need to do more maintanence on that tank.
What I'd be worried about personally is how you are going to feed all of those carnivore type plecs without letting the ones that it will be detrimental too (like your Panaque) eat it. Really want to try and sort it out asap to be honest mate, some of the ones you have mentioned are really territorial, good thing they are small. Then again I have seen overstocked pleco tanks work on the agression front so...