The MRC makes it easier to clean.
No need for XS-Pro on those lenses, the standard F-Pro is fine. Maybe on the 24-105, but only if you plan to stack a CPL on it, else there's no worry about vignetting.
I have them lined up through a guy I know who used to import them - they are a good price. That said, I have heard that Canon caps may be problematic on the XS-Pro line, does anyone have any experience with this?