Yes and no, not every character made it in and I'm trying to avoid anything too predictable while still making it tend toward chracter/role/faction seeming to 'fit'. When I was making the list I generally went through and gave every character 6 possible roles, sometimes all 6 were unique and sometimes their were repetitions where 3 of the 6 were vanilla. The norm tends to be 1 each of vanilla, scum, and roled. Some characters might have 4 vanilla slots, one role, and 1 scum goon option, another might have 1 vanilla, 1 scum, and 4 slots for the same role, where those slots are identical or might be 2 one shot versions of the role and 1 normal version and one other role that also fits the character. Some are a little shoe-horned in, where I basically wanted to give a less common role a chance of being in play and I just assigned it to the first character it seemed a halfway decent match for, giving it a 1 in 600 chance for each player to be in the game, and sometimes that meant it fell to a minor character who would otherwise tend to scream vanilla, which I felt helped balance the tendency for major characters to be more likely to have a role power.

Now in terms of plot, let me give you a 12-person example from the prototype for this I made for Wheel of Time, here's what I got: (By the way OS is for one-shot)

Mat - Cop

Sheriam - Goon

Flinn - Doc

Alviaran - Vanilla

Valda - Vanilla

Egwene - Scum RBer

Taim - Scum OS NK

Lan - Bulletproof

Ingtar - Miller

Hurin - OS Tracker

Thom - OS Vig

Tuon - Vanilla

As you can see the roles and alignment aren't obvious but they all 'fit', eyeballing that we've got 3 scum who have a RB and a one-shot extra kill, but we've also gotten a decent number of roles for the town with only 3 vanilla and 3 light roles one of which is anti-town, conveniently though randomly balancing out the little bit of extra investigation Hurin provides. So it's pretty balanced, maybe a little tilted to the scum but I have templates I can apply to nudge things and I'd feel comfortable personally going into this game on either side. Now having reviewed it all the things that 'stand out' are in my head, Alviaran as town and Egwene as Scum being the big ones. First thing that comes to mind is that are scum are all channelers and that Tuon and Valda hate channelers, so my skeleton plot starts by saying Sheriam has convinced Egwene to ally the Rebel AS with Mazrim Taim and the Black Tower against the White Tower loyalists and the Seanchan and Children of the Light and pressure Rand, who can enter as a NPC, not to ally with either the Seanchan or the White Tower, represented in game by Alviaran. Never happens in the books but it fits well enough, and just run with that, flush it out, etc. The random generator works kinda like a Mad Lib so it's actually kinda fun to try to come up with something, whatever that sometihng is will be heavily influenced by the series but its mostly the characters and their role/faction assignments that will influence the plot. I suspect a lot of settings would be kinda tricky to do this with but a lot the series that are pretty long and include a lot of anti-heroes or people working at cross purposes would work pretty well, and Dresden Files fits that bill nicely.

I can't give a direct example for Dresden yet, but I can say that just as with our WoT example stuff that has happened in the series will tend to influence how I'd draw the connections and that would influence plot, for instance here I'd probably drop clues in the intro and daily flavor like amidst a paragraph of text "... but the uneasy peace, however temporary, is hardly complete. Tensions remain very high between the Seanchan and the unconquered lands, particularly with the Rebel AS and the Black Tower being so close to the Seanchan's borders." Whereas if the evil trio had been Egwene, Sheriam, and Demandred I might have just gone ahead and had Egwene been turned by a circle of 13 Myrdraal and channelers and hinted at by dropping a comment to Hurin in a Night or intro Message like "You can smell that Fades have been here recently, perhaps a dozen or more" and one to Flinn like "Goosebumps all over your arms tonight, channeling and lots of it" etc.