Well, technically speaking as far as I know, a Mayor/Baron at the start of the game has that position along with a majority of ownership "stock" in that settlement. The difference between a Mayor and a Baron is simply that the Baron is a Mayor whom also has some form of a defense contract with the Duke or Duchess of that Duchy.
The same rules would apply though in terms of being Mayor or Baron of that settlement at the start. So, what you would need is a Brudvir in a settlement in their lands that is capable of having 51% ownership of the land in that settlement. I dont know enough to know what exactly it would take to insure that, especially prior to us seeing any Domain Selection maps, but maybe someone else will be able to add to this.
I do think it is possible but saying for sure would require us to have more information available to us than what is actually available to us at this point.
I hope this helps.
In regards to what you could do during KoE to help in that endeavor? Well if you cant find a Brudvir to take over in a settlement of your choosing during KoE then you might be able to take over a Brudvir elsewhere, move that Brudvir character to the settlement of your choosing and then work with your friends to make sure that said Brudvir is wealthy enough to start a Family in that settlement so that hopefully during Release the future members of that Brudvir Family will still reside in that settlement so you can choose them during Expo. I am no expert though, I could be wrong with this. There is more that we dont know than there is that we know.
