bill,
you can use your LBP 8.25 backing plates...brakes..and drums with those axles..i have swapped out two 8 3/4 like that...
but one thing according to Dr Diff...if you have the clutch style sure grip...watch out for the Yukon axles...he says they are too short to properly engage the sure grip.....in other words..they are too short...they only engage about 1/8 inch..
one thing went your order from him...he asks questions about your 3rd member...kind of kinky...