Do NOT commute on the street with race pads. Your pads and rotors will both wear EXTREMELY FAST. That said, you'll be fine swapping them in your garage the night before and event, and swapping back after you get home.
This depends on what brand pad you use. In principal I agree but, I'm a lazy sort so, I run my Carbotechs on the street and track. I find them to be the best pads period that I've ever used and they don't eat the rotors. I'm not concerned about dust or noise though and they are dusty and noisy.
I think you have a more fundamental problem than just pad selection. More likely the front brakes aren't pulling their weight so, the rears are doing too much work. Maybe this is pad selection like, too little pad in the front but, I wonder if your BBK is actually working properly. I've often run track pads in the front and cheap street pads in the back (though not on a subaru) and not had problems with excessive rear wear. You really want an aggressive pad for the front and some lessor pad in the rear. It'll keep the rear in check under heavy braking.