The Mavic disc specific wheels have a "Disc brake specific profile: no braking surface." (from Mavic) So I would not use rim brakes on them, only discs.
In my experience, there shouldn't be a durability issue w/ the various eggbeaters. The $$ difference is what you get for Ti. The stainless is just as good, little bit heavier, but significantly less $$. The eggbeaters are a great choice in pedals.