INFO:   1998 Legacy L Sedan, Automatic, 2.2l 258k 

BRAKE INFO: 4 wheel disc / ABS / single piston

So, just got done putting new calipers, brakes, and rotors on the rear of the sedan. Prior to replacement, every time I turned a corner, typically turning right, the RIGHT REAR made a grinding sound. I figured it was brakes, since there was some wear marks in the rotor. However, now that it's all done, it's still there. Wheel isn't bent, tire is new. I'm thinking bearings? Or maybe axle is bent? 

if you haven't touched the axle nut, likely the dust shield rubbing on the new rotor.  pretty common on subarus with disc rears.  you can bend it away or grind a bit of it off.  or just run with it until the noise goes away.

My first thoughts were bearings too. 

Did you spin the hubs while both rears where in the air without the brake disc on them? Perfect time to listen to the bearing - any noise or feelings of vibrations would give you a good indication of the bearing’s health. 

Cheers 

Bennie