HooHaa! Here I stand. For the moment I am the only guy on the planet with access to this final URL. Many thanks to all, especially Tinka, for all their help solving these fascinating puzzles. It has been a real hoot.
To clarify: I am the only MEMBER to have completed Synchronicity so far. Tynka is a MODERATOR and certainly shares the honor of having finished (well before I did). If Tynka had not already found the answers, I would not have been able to benefit from those gentle nudges toward answers that seemed impossible for me to get to all on my own.