So, here's the outcome. First, some updated pix:
Bolt carrier detail:
Trigger group detail:
Et voila, the finished product (sorry for all the clutter in the picture):
Overall, few issues. Problems to note:
1) I beat the hell out of the front sight getting it back together. Not worth stripping and refinishing now, but I will at some point in the future, since it's taken off the paint:
That was a killer for me, because I go nuts for a flawless paint job.

You can also see how my very tight-fitting safety selector has already scratched the coating, just as it did to the original surface. I thought about trying to bend that a bit before installing to loosen it. But, I figured that on such a slopping fitting gun, anything that was so tight must be that way for a reason, so I left it as it was.
2) The handguard comes with a set of spacers for the front and back ends which, in the case of the back end, serves to seal off the opening in the receiver underneath the chamber (see below, where I'm holding the piece in my hand, and the gap in the receiver, about 5:00 of the piece and just to the left of the vertical grip):
The problem I had is that, like many AKs, mine is not an exact length/fit. So, the only way I could lock the lower handguard retaining collar into the notch in the barrel was to remove both the front and back spacers from the handguard. Not the end of the world, since the receiver has other gaps anyway, but I am a stickler for putting things together correctly. If I have the patience when I refinish this gun again, I will probably grind down the handguard edge a smidge so that I can fit the spacers in -- although, by that time, I probably will have lost the spacers.
Overall, including tools, supplies and parts, it cost me about $300 to rebuild this gun from stock fugly as purchased in 1991. That's a bit more than outsourced Parkerizing would have been. But, I also got threads, brake, handguard, stock and cheap red-dot. And, I learned a hell of a lot about refinishing AK-pattern guns. So, all in all, a pretty good deal.
I hope to get to a range this weekend and zero both the irons and the red dot.
Lemme know if you have questions on the process or on Gun Kote. In fact, if I can establish a decent workspace after I find an apartment, I may start doing paid Gun Kote refinishing as a side gig. About $500 in equipment is all I need to supplement what I already bought to get to a pro-level setup.