I definitely remember an episode where Ned is a card-carrying senior citizen.
I think Fallout Boy is actually thirty or something. (But then again, Kearney might also be thirty.)
Jaquelin Bouvier should be a senior citizen, and apparently is not. She might also fit as a pessimist, she's often very negative.
Miss Hoover should be a pessimist.
It seems like Luann should be an entrepreneur, since she runs the cracker factory.
Kirk should be a pessimist.
Princess Penelope should be a celebrity, since she has a task at Krustylu to record a show.
That's off the top of my head. I think you covered most others I was thinking about.
(BTW, your thread title doesn't really convey what this is about; I thought it was asking about who was in the existing character groups.)