I can walk you through all of it and have helped may do so.
The axles can be checked in the car no problem. you just need a 9/16 socket with a extention and some muscle. remove all 4 bolts and then remove the retention plate and pull away...you should use a axle puller tool...BUT I know people just do not have these specialty tools laying around. SO, if you can get a pry bar behind the axle and brake cylinder and some other ideas like a 2x4. If you can get a couple of the backing plate bolts back on the flange with out the axle retaining plate that will give you a good sturdy place to pry against again. Then agian you may get super lucky and it will just pop out. If you car is driving and not been sitting to long it should pop out with little effort.
The diff rebuild would be alot ALOT easier out of the car.
Besides don't you want to clean the undernethof the car and paint up the control arms etc. NOW would be a great time for that.
Jim - J D Race
GM Diff specialists