Progress happens. I would like to say that as I approach the fifth birthday of this thread (You read that right... about to enter year six of this build), things are just about done. I could say that, but it would be either disingenuous or jinxing - I don't know which.
In either case, progress does happen. I have managed a couple coats of the same water-based paint I used for the speakers, taking Bryan's advice that any paint needs more than one day before applying any pressure to it and expecting it not to peel. Even better, in the last two weekends - with paid help - I got a door jamb built and installed and the door hung in it. Woot!
The painted inside still needs another coat of paint, and the handle is not yet painted.
The outside surface is just sanded and sealed. It still needs primer and paint. There is some assorted other patch work to do before it's fully beautiful, but it's coming along nicely. It hangs well and swings quietly. Door bottom is installed, and the stop positions are marked and were temp installed to assure proper closure.
I have stuck with the roller latch for closure. With slight modification, I have so far been impressed and remain optimistic that it will work.
The latch is made of a roller held in position by a spring. When shipped, the roller spring is the lighter set of the two (two sets, four springs) while the overall adjustment is set with the screws against the heavier set of springs. Maybe you can see that in the image I found of a latch like mine, below. I disassembled the latch and swapped the spring arrangement. The result is that I have very little leeway for adjustment, but a very strong set of springs holding the roller against the strike plate. As you can see (above), we decided it would be easier to mount and adjust if the strike plate were on the door with the latch mounted in the jamb. Maybe I just got lucky in having the door slab just he right distance from the jamb, but it seems to work really nicely for now at least.