Yes.
I stayed there two weeks ago, under a special room rate set up by an event promoter. Flew in, only to discover that I had need of a rental car for one day. I think their parking fee is steep (and I've paid daily parking up & down the NE corridor), so I politely asked the desk clerk, "if parking was included"... she was happy to comp me. I later learned the event rate did not cover parking, so it's clear this was purely a courtesy by the hotel. The only hitch in all of this is that their parking facility is operated by a third party, not by Sheraton directly, so you can expect some communications issues between them. Still I saved a good chunk of cash, just by asking.
Yes, but its paid at a daily rate. The cost is in addition to the room rate.
Yes, in an attached garage, and the rate paid in late June and early July was $28 per day.
Yes! Valet and self parking.
Thanks! Your answer is awaiting moderation.