The only use for RAW over TIFF is if there is bad highlight or shadow detail in the photos. If your wife-to-be is wearing a white dress on a sunny day, RAW may be a good idea for the outside shots, but if the photographer knows what he's doing, it's not necessary.
It will be difficult to convince the photographer to use RAW mode for the ceremony and reception, as it requires more time between shots. You may want to consider it if you are having a studio session, though again, if he knows how to light, it won't be an issue. If your photographer doesn't know enough to properly expose his image, it's pretty likely that he'll just make it look worse through any RAW editing he does anyway, IMO.
The difference between JPEG and TIFF is not anything you will ever see in a print, and you won't even see it in the file unless you apply extreme corrections that you would never apply if you wanted to make an image you could see anyway.
The caveat to the last statement is that it assumes the jpeg has been saved at the highest quality setting. If the photographer doesn't know what he's doing - either in camera or in converting RAW/TIFF to jpeg - there may be degradation.
Last I checked, the RAW plugin for CS was $100.
IMO, RAW files for your situation are not worth the time or money. If you can talk your photographer into shooting RAW, it won't hurt (but isn't necessary), but ask for TIF or JPEG's for your personal work. If you ask for JPEG, just specify that you want them saved at max quality.