Am I correct in assuming only the inside pads on each rear wheel are functional with the parking brake? My outer ones don't move when pulling the handle, but then again the system needs to be bled so that might be an issue. I just thought the parking brake was purely mechanical

Purely mechanical, inside pad only.

Thanks, that helps!

I'm certainly no expert. I was under the impression that when the parking brake arm is engaged, if the brakes are properly adjusted of course, pushing the inside pad against the rotor will also engage the outer pad because the tolerance is so small. I may be wrong...