Point A - for long term storage, the shutter should not be in the cock and ready position. That will leave the mirror in the up position, which I guess relieves the tension on the spring assembly.
In regards to point B; I just looked at pg 21 of the pro, pro-s, and pro-sd manuals. I don't see a film advance knob in the lower right of any of the backs. I also have many pro, pro-s, and pro-sd backs, and don't see a second advance lever. The only advance lever I see is the 'regular' lever.