Rotten Egg, or a sulphur smell, is usually an indication of a catalytic converter issue, the metals inside can produce that smell. With the a/c in "recirc" mode, you are shutting out outside air from coming through the vents, recirculating the air that's inside the car, essentially blocking the smell from entering the cabin. The air intake for the climate control system is at the cowl vent at the base of the windshield. It's possible there is a failed seal somewhere, or an open seam down further on the firewall, allowing the sulphur smell into the car. His car probably has catalytic converters right at the engine, which could explain why exhaust smell is coming through the dash vents.
I sometimes smell sulphur if I have run my truck extra hard for some reason. If your smell is a mold/mildew smell, then Borger's probably right.
On your G5, are you trying your windows from all possible switches? If the window stops working from the driver's door switch, are you then trying it from the switch at that door? If not, do that (if they work at their own switches, you know it's not the motors, it's gotta be the switch), your whole problem could be either the connection to the driver's door switch or the switch itself. A bad connection there could cause other electrical issues, including your instrument cluster problem.
The noise in your wheels could be a bad wheel bearing, among other things. See if you can isolate the noise to a single wheel, could be front or rear. I would check it by driving in an area where a good noise bounceback is possible with your windows down, such as next to a jersey wall, this will hold the noise in, amplifying it, allowing you to pinpoint the source.
All these issues sound like warranty concerns to me, why not let the dealer find and correct these things?