I like this idea! But personally, I don't think going by highest follower count to decide the order is the greatest idea. While it would ensure that whoever claims the role that month is definitely established in the game enough to follow through, it would also heavily favour older characters/players who've had years to accumulate followers. I can see how that makes sense on an IC level, but it might be a bit of a downer to some players to know that it might be months upon months before they have a shot at it.

Maybe instead of going down the follower count rankings, there could just be a minimum follower count requirement (10k? 15k? something like that?) and have players sign up to volunteer for it. That would skip the hassle of checking everyone to see who's actually interested or not as well as open up the option to more players/characters who'd otherwise have to wait ages to get their chance.