Phentari wrote in The Strategic Review #6 plus a bunch of other stuff...:So, questions:
2. Is there a proper way to care for minis this old?  I hesitate to just pop them in a jar of Pine Sol, but I'm worried about lead rot.

I'll let other people answer the other two questions.  Lead rot is a real concern for older minis, but I would not go the Pine Sol route to preserve and store them.   As soon as the jar gets broken, or the plastic container cracks, you've got a real mess.  Pine Sol is one possibility to remove old paint, but Simple Green is better in my opinion.  One week or so in Simple Green and an old toothbrush should get rid of most old paint.

If your friend wants to keep the minis, I recommend washing all minis in water, scrubbing them lightly with an old toothbrush to remove any lead rot already present.  You will remove paint on top of unseen lead rot as well for minis that are painted.  Then dry them.  For painted minis where you like the paint job, I'd spray them with Dulcote, including the bottom of the base.  For paint jobs you don't like, remove the paint with Simple Green, then wash and dry them, and then spray them with primer, including the bottom of the base.  The primer should protect them until they are painted, even if it is years later. Armory makes a good, grey spray primer.  Then store them in a box where they won't bump into each other much, or at all.

If your friend wants to sell them, forget all that and sell them as is.  Do not go to any trouble washing, priming or whatever.  People sell minis like that all the time.  Just state in the listing that they are old, probably contain lead, and show close-up photos of everything.  

Appreciate the advice, guys.  Thanks!