macnbc: As far as 1 and 3 go, that's been discussed elsewhere on the forum, and while I'd say 3 is certainly possible, the first game presents some technical challenges, since it was a Windows 3.1 release.
JMP4 has no chance though. I've heard statements from team members multiple times that very little work had been done on the game before it was canceled, mostly just some pre-production work. If there will ever be another Journeyman Project game, it would pretty much have to be started over from scratch, which isn't likely since Presto has gone out of business. (There's just one or two people there maintaining the company records and legal presence.)