Consensus seems to be that the older M-B transmissions aren't picky. Last time, I added 1 qt of Mercon VI (Ford), based on opinions here. But, will probably use ATF+4 (Chrysler) next time since I have it and many brands are full synthetic. It is mandatory in Chrysler transmissions, and shops installing cheaper Dexron III ruined many transmissions (mostly V-6 minivans) since that caused "shudder" in the lock-up torque converters, but the 700.3xx and .4xx M-B transmissions don't have a lock-up so no worries. Many racers and classic car owners like Type F (old Ford) since it gives faster, firmer shifts which also reduces clutch plate slippage and wear.

Foaming isn't necessarily bad. I understand the main feature of Dexron is that it purposely foams, which helps keep the inside walls of the transmission case clean.

Re power steering, ATF isn't necessarily a bad choice. Indeed, a Chrysler TSB says to install ATF+4 in all their power steering systems (even 1960's Pitman arm type) when doing major work. That is to reduce flow noise in long hoses (similar problem in M-B SLS hoses). So, unless the Vicker's p.s. pumps are fundamentally different, it "should work" and I use it in my 300D's.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans