I am reliably informed by a mother (not mine) that ignoring a kid throwing a tantrum will short-circuit it. Danged if it don't work with cats, too! These past two nights, I've refrained from reacting when Minnie lets loose with her high-volume yowling in the most echo-ey part of the house, and in a fairly short time, she quits, having gotten the clue that I'm not going to get up and let her outside. At least, that's the way I'm interpreting it. I've also put a window-height cat tree in my bedroom and left my metal blinds open far enough for Minnie to get up and walk around on the window sill (which is 4-5 inches wide, plenty for a cat to sit and observe the world outside)--that has helped, too, I think. She has even condescended to get up on the bed and sleep with me (for a while, anyway). So things are improving.
We're no longer locking the cats in our bedrooms with us at night; that stopped working on my kitty after just a few nights, and Sammi, A's kitty, really seems quite at home. She's more "mellow" than Minnie.