If she hasn't talked to them a whole bunch, I've noticed if you talk to them 1-3 times only, and ignore them for about a week, they'll ping you about wanting to move. Fastest way I've experienced~
I've wanted Bluebear out of my town for a few weeks but i talked to her about 12 times and did her favors 2 times, but she's never offered to move.
I literally got Benjamin, Henry, Kody, Clyde and Hans to offer to move within 5-7days by talking to them once and ignoring til they ping to move.
I've heard a good way is to time traveling two days forward, then two days back and someone will normally ping you about leaving.
It's all random though. There's no real way to enforce someone to leave or not sadly unless you do time travel. Friendship levels don't really matter as much as most people think. Or hitting them with hammers, nets, etc. most people get lucky with the rng in-game if that type of stuck works lol. I wish it could be easier though, getting unexpected move ins is the worst.