from the pics on the first page it seems that the drums have never been machined. I'm assuming you're not looking into replacing them, just take them to your friendly neighborhood brake shop or anyone that knows how to work a lathe.
I think you're fuzzing too much about those rear pads. if the parking lever is traveling too far, adjust the brakes. Otherwise, you're fine for a good 6 months or more. When you actually have to replace them, just dismount one side and take them with you to your favorite parts store, the attendant will just have to take one look at them to tell you if he can help you, or he'll point you in the right direction.