Sure enough, once I installed the new Developer Tools and rebuilt X11 Emacs, it works just fine! So we are now good to go for future development work, and I can go to bed with a happy heart.
Total time spent installing Panther and related tools, plus recompiling Emacs: two and a half hours.
Most serious problem: boredom while waiting for the installers to finish.
Only glitch encountered: I had to ask Fink to recompile Emacs for me.
I’ll probably have a little more to say about Panther tomorrow. But for sure, Expose is way cool.