Yeah,, I've done both of those tasks lots of times. I emailed Mike Dorffler years ago about the foam for the pressure plate, and he confirmed that it was standard Ace Hardware open-cell insulating foam. The stuff in the hardware store has adhesive on one side and you need to use contact cement for the other side. Get all the old stuff off with alcohol and glue on a new piece.

The rubber band is somewhat more difficult to replace since you have to pull the pulley shaft out of whatever it is stuck into on the other end (I forget the details at the moment). It is friction fit so you can pull it out without damage. Just make sure you get the pieces back in the right order including the little Teflon washer. You don't have to pull the drive shaft completely out of the camera, only enough to slip on the new rubber band. I can't recall the size at the moment, it may be a #10 band. The rubber band drive only puts enough tension on the takeup reel to keep it somewhat taut, the claw and gate mechanism is what really advances the film. Note that some takeup reels have tapered shafts and some are not, one will work with the other one but the other one won't with the other one and I don't remember which one will or won't If you only have one and the corresponding cartridge then it won't matter.