Plasticville!
Question definitely solved. (It's amazing what you can ferret out if you're willing to whiz away half a sick-day doing it).
These are Manitouguy's photos of the larger-scale versions of my HO figures.
He claims they're Plasticville. He also says the standing figures to the left and right of them in the photo below are Plasticville, but I haven't dug up any verification for that, and I doubt it. I'll bet they turn out to be Monogram or Revell or something.
Note that the seated figures are either a smaller scale, or are exceedingly affected by the wide-angle camera lens. Since he verifies the standing figures are 54mm (1:32), I'm guessing that Plasticville did these figures in 1:48 scale, so they'd mesh with P'ville's other figs intended for O scale model train use. This would square with
Slotrod's comment.
I went to the P'ville Collectors' Assoc. page, because I remembered they have good images of practically everything Bachmann ever marketed under the P'ville name, and the boxes too. Frustratingly, they've now fenced off all their pictures in a
members only area. To access it I'd have to apply over the web, they'd mail me a paper form, and I'd send it back with a check for ten dollars. I could afford the ten dollars, but not the week of folderol. Thank heaven for Wayback.com. Earlier versions of the site were in the Wayback archives. And here's the smoking gun:
Poor artwork, but clearly the same poses. Even has the hot-dog vendor. The link to the box for the HO version (2777) led to the Hot Dog Stand box, so I don't have an image for it, but I don't think there's any doubt.
-- D