MB does have approved product lists that come with the new cars, yours probably came with one originally. If you call MB at the 1 800 FOR MERCedes number, i bet they'd mail you one for free.
On the coolant, the MB coolant is rather yellowish looking, not green. Recently they switched to a blue coolant, but what the dealer sells is still the yellow stuff. The overall effect when it gets old is indeed alot like dexcool, yellow-orangish looking, so I wouldn't sweat the water/rust cooncern, but comendable that you'd notice this. MB stuff is really preferred to use, but if you aren't near a dealer, just get something which is specifically intended for use in aluminum engines, even though the MB engine usually isn't all aluminum. Stick with the name brands.
Brake fluid, again MB is preferred, if you can find another brand of DOT4+, then use it. It's NOT silicone though. Should be flushed at least every 2 years, the coolant is supposed to be done every 3 years.
The transmission fluid, use a good brand name DexronIII/Mercon. The torque converter has a drain plug, in addition to the transmission pan. Have to rotate the engine through and watch for the drain plug. Only rotate the engine in a clockwise direction as viewed from the front of the engine, don't rotate counterclockwise.