Thanks for all these ideas!

At present I am leaning toward building up the curbpick Nishiki mixte. I will try to find a used 3 speed hub and shifter, some upright bars, fenders and chainguard at the local coops. I will probably take a chance with the cheapest generator hub I can find, which I will try to disguise & uglify, and to protect with the linked VO antitheft skewers. Or a cheap bottle generator. Plenty of reflective tape on the fenders, cannibalize the reflective sidewall 32mm Kendas from the UO-8. The milk crate basket / pannier sounds both practical and theft-deterring. This will rescue a frame from the trash pile and should be a skirt friendly beater campus ride.

There is something neat about a beater bike that turns out to have tight, true wheels and be perfectly adjusted and a great ride. Sleeper bike.

As for the other bikes, my son will be going to high school next year and is outgrowing the small Novara hybrid he started riding to middle school. I might put him on the LL Bean MTB or the UO-8 as his school bike. His school bike leads a decent life, because it comes back to the garage every afternoon and gets regular maintenance. He'd be riding about 8-10 miles a day, with some modest grades to climb.