Yesterday I put on the fourth run of my narrative tabletop game, The Bloom of May, for a wonderful group made up of inwaterwrit, john_in_boston, pezzonovante, and phoenix_rinna. It went very well, they were a great player group who represented their characters beautifully and did a great job of carrying the story along. This was also the first time I ever ran with four players; I decided to make Sprig Jameson an NPC, and that actually turned out just fine, though I definitely prefer her as a PC. The game is a bit too GM-intensive to fully embody a major character in addition to running, but it works fine as long as she's present when the other players want to talk to her, and injects her information at the appropriate points of the game. That's how I'll handle it in all future instances of only four players.
It is interesting to note, however, that she's the only PC who must be female. That may surprise you if you know the character, as she is really not a strongly gendered personality in any way, and she was written originally for niobien, who I think would have been equally fine playing a male character. But due to a very small but extremely important technical detail in the plot I can't think of any good way for her to be male. Of the other characters-- Alice the heiress, Lucy the actress, Matthew the carpenter, and John the cop --their flexibility is varied.
Alice and Lucy turned out to be totally flexible, turning into Alexander and Luke, as long as I flipped the genders of some of the other NPCs. The story is intended to be set in the real world with as much historicity as still allows for dramatic action, so if something like homosexuality features it can't be incidental, it would have to be a plot point, and this story isn't really designed to accommodate that. Also I may want to include a storyline involving that in the future, so I don't just want it tossed off.
As for Matthew and John, they've never been played so far as anything but male. John as a police officer might be difficult to gender flip for the 1930s setting, I'm not sure a woman cop would really be possible. But maybe Matthew could be a female carpenter if she was seen as something eccentric. That might be able to work. Especially since, now that I think about it, Matthew's already something of an outsider to the community due to the fact that he's one of the few Jews in Fairfield.
Speaking of gender flipping, the genders of the relevant NPCs not only based on how many are flipped, but in what combination they are flipped. I discovered that if I'm playing with an Alexander and a Lucy, I have to add an extra NPC that I didn't originally plan for. I discovered this when bleemoo played Alexander, and I had to do it on the fly because I hadn't anticipated it before the run. If I have an Alice and a Luke, I have to flip an NPC and add a DIFFERENT extra one. If I have Alexander AND Luke, though, at least all I have to do is flip. That seems strange, but it becomes clear why once you see how the plot of the game works.
What I should probably do from here on out is say that, okay, BOTH the original NPC in this instance as well as the new one I've had to add exist in game, all the time. But, depending on the gender balance, one will perform the function of the original as written, and the other will either perform the half of the function they can't, or else just be a background character if they are not needed. Confusing, I know, but it's the only way to make the game work!