Re: 94 Merc Marquis Windows/AC Q's??????
Power windows are DEFINITELY the weak point of those cars. I don't know about the newest ones, but we've had an '85 Mercury Grand Marquis, '85 Lincoln Town Car, '89 Ford Crown Victoria, and '96 Ford Crown Victoria. ALL of them have had power window problems.
The ones that will go down if you push them are probably just bad drive gears, which you should be able to buy at your auto parts store. (I would recommend getting a shop manual for the car if you haven't already; I've seen those newer power window systems and I still don't understand how they work, so it may not be intuitive). As for the driver's door, do the cables that come out of the motor assembly run up and down when you operate the button? If so, that one might be okay if you can reattach everything the way it's supposed to be. Look at the other windows to see how they go together and you should be able to put it together.
As for the AC, if the compressor is cycling on and off every 10-15 seconds (give or take) then that is a definite indication of low refrigerant. It will use the R-134A refrigerant, so there's no conversion to do. The charging point is on the passenger side near the fender well. There are two points that have caps on them like a valve cover on a tire. One of those (I think it's the forward one of the two) will not fit the hose that you buy, but it will go on the other one. I believe that it is near the cylindrical shaped piece that is near the back of the engine compartment.
Also, being that the refrigerant leaked out, you might be wise to buy the stuff that has stop leak in it. Our '96 Crown Vic was in the same situation as yours, blowing "luke-cool", and we put the stop leak refrigerant in it. So far, it has continued to work great.
Sorry to be so long winded, but I've had a fair amount of experience with these cars, so I have a fair amount to say. If you have any other questions regarding this information, feel free to ask.
Nathan in MN