SF- Harry; Murphy; Susan (Michael, Anastasia, Carlos)
FM- Harry; Murphy; Alphas (Susan;' Michael, but only in 5 person games)
GP- Harry; Micheal; Susan or Thomas (Murhpy)
SK- Harry; Alphas; Murphy (Michael, Anastasia, Carlos)
DM- Harry; Michael; Sanya or Susan (Thomas, Butters)
BR- Harry; Murphy; Thomas (Alphas, Butters)
DB- Harry; Butters; Thomas, Anastasia, or Carlos
PG- Harry; Murphy or Thomas; Molly or Michael
WK- Harry; Molly; Thomas or Carlos (Murphy or Anastasia)
SF- Harry; Michael or Sanya; Thomas, Murphy, Molly, or Anastasia
TC- Harry; Molly, Anastasia, or Alphas(choose two) (Thomas)
Rules given for 3 or 1 person game, as those are what I will mostly play, it is the smallest number of characters you might need, and it is the one number where I could be sure of really relevant options for every slot in every book. For two or four person, choose an additional option from the normal options if listed if possible. For 5 person games, choose two more optional characters, but only one per pool if there is more then one pool of multiple characters as separated by a semicolon (for example, a 5 man SF game, you could have Harry, Michael, Sanya, and two from Thomas, Murphy, Molly, and Anastasia; you could not choose Harry, Thomas, Murphy, Michael, and Molly however).
For books with fewer characters listed than the number of players, choose from the parenthetical options, but only after exhausting the normal list. When possible I populated this with characters who played a roll in the book, but one that is relatively minor in comparison to the core options. When not possible, I either went with characters who existed in the world and are not excluded by a specific plot point (IE Michael was clearly around as a KOTC since before the start of the series and Harry met him sometime before BP, so he is an optional extra for the first two books, but not for BR since as that time Harry was purposefully avoiding him do to the coin), or by characters serving as stand-ins for other non-playable characters (Anastasia and Carlos in SF and SK essentially representing Morgan/The White Council as a whole respectively).
Note I did not include Mouse in any of these as his is the only deck I haven't ordered, but he almost certainly fits somewhere into any book from Dead Beat onward. I'd have to think about how to slot him into various pools to keep the priorities correct though.