Not sure if this is helpful! But... whenever I'm paranoid/unsure if one of my favorite villagers will move out I TT up to two weeks ahead, start a new game with a new character, then check if there's any missing houses. The missing houses are the impending moveouts. If you go back to your normal time you can prevent or encourage them when they ping you (and they *will* ping you, this is pretty inevitable). This makes it much easier to pinpoint who'll move out soon and also prevents surprise moveouts.
It's not very convenient since you'll be changing system settings and have to sit through the whole Rover thing, but it's pretty safe as long as you only start a new character in the future (NEVER LOAD A CHARACTER) and don't save. I've prevented moveout of a couple of my dreamies this way when I was cycling out villagers.
It's also possible that you travel forward in the future and all the houses are still there. This only means that nobody has thought of moving out yet in your last save.
(sorry for words D: )