A & B service
#2
If you have the set of manuals, these services are described in the maintenance book. The A service is basically a glorified oil change. They check the fluids, top them, and also do some other minor checks on the system functionality. The B service comes after the A service and involves everything done in the A service plus the A/C filter, air filter, wiper blade, tire rotation in some cases (some make you pay for this), weather striping cleaning/lubricating. Then the services alternate from A-B-A, etc. If your vehicle is just turning 2 years, then at either of these services, they'll flush the brake fluid. If you do it outside of a A or B service, you pay. The coolant gets dumped after 3 years and the plugs at 100 miles, I believe. There are probably some more technical stuff they do that those of us outside of the MB shops don't know about.
#4
I don't know what information all the dealrs give out, but I'm sure if you ask, they'll tell you all that was done. I usually just take my service record booklet along and they'll put a check mark on every item that was worked on. Of course, if you don't have the service record booklet, just ask them to list the work done on the work order. It shouldn't be that much of a pain for them to do, and you may actually get more info that way.