Isn't Marvel Mystery Oil made from the first cold pressing of virgin snakes?
Stabil is a fuel stabilizer; keeps your gas from going bad if it's going to sit for an extended period. Some people say to use the marine version as it has less alcohol, I think? I don't know; my fuel doesn't stick around long enough to need it.
Crush washer - BMW parts listings usually call them "gasket rings." The small aluminum or copper washers you find under drain plugs. Screwing in the plug crushes the soft metal against the case and the bolt, sealing the gap between them.
Never heard of Aero Kroil until now. Googling it, it appears to be a penetrating oil, for loosening stuck bolts etc. They claim to be the best, as do all the others.