I'll try an answer a few for you -
1 - All of the film I shoot ends up getting scanned into a digital format, so I prefer to shoot low contrast film which makes it easier to scan well and I can then add contrast if needed in Photoshop.
2 - If you plan on getting large prints or highres scans at a later stage, just get the lowest res scans for proofs onto a dvd, makes it easy to check through your images and they are good enough for the web.
3, 4 & 5 - Most likely your images will be supplied as Jpegs so will open in Elements depends on what your Lab uses to create low res scans, my lab just uses a digital camera so they are supplied as Jpegs, you could probly request Tiffs if you wanted to a small amount of editing to the proof images.
and its always better to use tilt/shift lenses if you have them, whether creatively or correctively.