Thanks again to all who posted.
I've ordered the replacement sealing sleeve. I'm tempted to top off the fluid in the next day or two even before the sleeve comes in just because I'm paranoid since I don't know how much has leaked out and I expect that the car won't go into some sort of safe mode due to low fluid in time to be able to save part damage, anyone? This will also give me an idea of how crucial the pan drop is to getting at the sleeve.
Oreilly doesn't have the Motorcraft Mercon SP fluid around here so I'm going to the local Ford dealer who has it for $7/qt. I've heard ranges of one to six quarts on different pan drops.
When the part comes in, I'll probably do the fluid replacement and keep the pan for now. I'll post back when there's something else to report.