From what we know from the datamines, villagers are excluded from moving out if they are any of the following: 1) the most recent move-in, 2) their house is being moved, 3) their birthday is within a week, 4) they were the last villager to ask to move out. So in this case, it's just bad luck. There's been accounts that the most-recent villager can move out, but it's probably the result of a bug. So unless you see Zell asking to leave at some point, Freya still has the ability to leave.
The Amiibo-specific glitches have been fixed since March.