Just wondering: what's stopping you from talking to the count/duke of your desired locations, prior to just choosing a settlement? Dukes choose next week, and counts the week after, which would give you plenty of time to try and figure out who is who/where. I suggest using Discord and joining the kingdoms in your server, which will make it easier to connect.
To answer your question though, it really depends on the duke/count. I think most people are expecting a good number of 'randoms'/unaffiliated folks just spawning in, mixed in with unknowns and possible NPCs. You might even be lumped in with NPC mayors, and therefore more vulnerable to aggression if people have expansion on the mind. You could also just get lucky and find leaders who are happy to just farm up. I personally wouldn't risk my investment/enjoyment like that, though.