The problem with the early Benz A/C units is that they were all "add-on" options installed by state-side dealers. You could have all kinds of components depending on what the dealer used. Could be Frigidare, ThermoKing, "Hey boss, Joe's got this set-up he fabbed together" brand, etc.
That's why I recommended you go "whole hog" on the system. The York compressor will work fine on R12 but I don't think it will be up to snuff pumping the R134a.
Check with a local A/C specialty supply house not AutoZoo or its ilk for possible matches on the dryer.
Can you guys even get R12 anymore in California?
Examine that rodent closely. Determine if it is indeed a common field mouse. If so, then "no" it doesn't belong there. However, if it is a "maus" then that was an option available only on the grey market import cars!
Stuff a neighbor's cat into the vent overnight to remove any further infestation.