Maybe I've misunderstood the question! What I was trying to say is that villagers won't suggest PWPs to people other than your mayor that the number of characters you play won't change the number of PWPs. But I might still be off the mark here.
Only mayor can sit in the chair in the back in town hall to do the mayor duties (talk to isabelle about PWPs and stuff) so non-mayor characters probably can't get any PWP suggestions from villagers.
I've read a few times that it is possible to get more than one PWP request per day. Tho they are like many hours apart.. Like you'd get one in the morning and one in the evening or something. And in my experience I've only gotten one at the most. So it might be rare occasion..