I don't usually adjust my damping much, so I'm not going to give you input there. It sounds like you have a good feel for how to set that up already.
Rear toe is tough, I don't play around with it much, and I don't know how much you can get out of the car by adjusting it.
I would add a little toe out up front to help your turn in.
RS3s love heat and camber, the focus loves front camber, get some front camber!!!!
Trail braking and Left foot braking go hand in hand. Use trail braking where you can to get the car rotated. I use trail braking a lot, though right now I am finally getting really comfortable with LFB and I'm working on braking harder for shorter durations.