Okay so, ex time traveler here, now I'm someone who takes 9 month hiatuses. xD
I can confirm that the stop villager from moving method works. What you should do is is this:
Get one villager to give the 'rumor dialogue' of their personality type (nothing involving your player is such a bell pincher or those things, no the 'rumors are so scary' 'before you go repeating a rumor it's best to look into it yourself' etc. dialogue). You can find what dialogue it is online but if you aren't sure you can screenshot it and show me here, I have no problems helping.
If that one villager gives their rumor dialogue: the others in your town are confirmed to not be moving.
If that one villagers says someone is thinking of moving: you have to find and have that villager ping and stop them, if this happens you can save and turn off your game, timetravel in ONE step and everything will be fine.
If the second option occurs you are done now. If the first option occurs there are some additional steps to take, as you might have been talking to the mover! There are two ways to find out.
1: get a second villager to give their rumor dialogue, if this occurs you can save and timetravel safely.
2: get the villager who gave you their rumor dialogue to ping you, if it's a moving ping you can stop them and save and timetravel, if it's a ping about anything else that villager has just been confirmed to not be a mover and you can do the same.
Hope this helped, let me know if you have any questions!