Discs rubbing no matter what I do
The first thing I'd check is that the wheel is mounted in the frame straight and fully in the dropouts - sounds stupid I know but we've all been caught out by things like this.

I wonder if somehow your hub is not running true, either because it's not running true on the axle, 

Remove the brake caliper, spin the wheel with the bike off the ground and verify that the hub body does not have any run-out. Do the same with the disc rotor - you can attach a  trimmed zip-tie to the seat stay to give you a point of reference. I'd check both lateral and radial run-out.

Once you have verified the rotor is indeed true, re-retract the pistons and align the caliper carefully. USing a flashlight and a piece of white paper to look down through the caliper can help you spot where the rubbing is occuring.