As to the question of wadding; this can be made with any number of nonsynthetic materials: cotton, canvas, wool, paper, foil, cardboard and maybe even leather.
Balls can be made out of car batteries, wheel weights, lead flashing, still used on roofs from time to time, and plumbing fixtures, some lead/tin solders could be used. Molds should be purchased ahead of time but in an emergency could be made from clay, wood, or plaster (results may vary).
For around $200 bucks a large amount of black powder and primers and lead balls could be put up for years of shooting.
True black powder can lasts for many many years as long as it is kept dry and in a sealed container. Black powder substitutes are also available but I'm not certain of how long they last.
I'm sure black powder can be made at home, but I don't think I would try. (OK, I would try)
Smokeless powder SHOULD NEVER BE USED IN A BLACK POWDER FIRE ARM.
(NO REALLY, NEVER!)
*I posted a similar response earlier, but I don't know where the hell it went?"