I think I also like the third option best. I´m a big fan of an events-board and a roleplay-board too. I think if that doesn´t turn out too chaotic, all the events should go there. Since all the event-threads are only active during the event and locked afterwards, I don´t think there´s a high probability of active threads getting lost.
To the perssssona-board, I think this one could even be completely moved to the Roleplay-board. Basically all of the threads there are dedicated to current roleplay, past roleplay and writing characters and backstories that could theoretically be roleplayed with. I maybe saw once or twice that people used it to show off their characters for fan-fiction they´re writing, but that does seem to happen rarely. It is a nice preview sometimes though, so if people still want to do that, a new thread exclusively for it could be made in the Creative-board.
But I do think that all the threads in the perssssona-board are very intertwined (Like, one thread is for the characters themselves, the next for their dreamspaces and so on...), so I fear that moving them under a different topic with more threads might let things get lost. If there´s the possibility to move this board as a whole rather than seperating it, I think that would be the best option.