Rear end conversion

The stock hand brake cables will work . I went with 11x2.5 rear drums and backing plates and the stock (But new ) handbrake cables worked fine. Are you sure the B-Body backing plates will work with your axles? I think there is a difference between B-body backing plates and A-Body plates.

All BBP backing plates are interchangeable, body style doesn't make a difference. The only reason there are different A-body backing plates is because of the SBP axles. With BBP axles, the B-body plates will work fine.

Are hand brake cables different than foot pedal parking brake cables? Anyone know if 8-1/4 cables and backing plates will work on an 8-3/4?

The emergency brake cables are not axle specific, you can use the 8.25" cables on an 8 3/4. All 8.25" backing plates would be for BBP axles and would have the BBP axle flange offset, so as long as you're using them with BBP axles they will work with an 8 3/4 housing.