Good choice. I would imagine yours will have the 722.6 transmission as does my 1996 E230. This takes only Mercedes genuine fluid. Although Valvoline Maxlife works. I've used Valvoline in mine and it works fine. Although I wouldn't advise mixing different fluids.

Not sure on your green fluid from behind the gear box. Could be antfreeze tracking from the back of the engine ?

I know when my atf was changed the first time it was yellow. Apparently it does this with age.