(Too Many) Characters Welcome

So as I plan for NaNoWriMo, I’ve been tossing around a few ideas. I really wanted to work on my sci-fi themed story, but technically, I’m not supposed to as I have already started it. I only have 8K words so far, but I wouldn’t count them in my totals written for the month, if I went with this story.
One in particular keeps coming to the forefront as I jot down brief notes for characters I may want to write about (their names, their appearance and the like). These characters are part of my medieval family I created when I wrote The Heart of The Panther. My critique partners may remember Gillian and Royce, and Gillian’s brother Simon and his “from-another-time-but-really-from-his-time” woman, Caroline. I know, that was confusing. But years ago, I started a story involving Gillian and Royce’s daughter, Marisa. I got about seven chapters into that one and it kind of withered and died on the vine. The plot was illogical, as were some of Marisa’s actions. But I’ve got a new slant on her now, and her nemesis Iain, the Scottish warrior who wants vengeance against Marisa’s father. So I’m leaning toward writing that this month – I have an opening already in mind, and I think I can reasonably tie in a bunch of kink to really spice the story up. It should work well, considering that opening scene does place her in a captive role.
The catch? I have a really great (IMO) idea for Helene and Devlin’s daughter as well. Since the Marchand men are happily and proudly Dominants, I wondered what a Marchand woman would be like. I tend to prefer to write my stories with a male Dom and a female sub, though I do enjoy reading a good ménage where there are both female and male subs in the relationship. But I cannot get into the mindset of a female Domme, or a male sub to be able to do a story like that justice. I guess I’m wired to prefer a male Dom and female sub. But being that Regine Marchand is a headstrong, independent woman, it should follow, that as a Marchand, she would be natural in the Dominant role. But I couldn’t help thinking what if she was truly a submissive, and didn’t recognize the fact?  And I have just the guy to show her how to face the reality she isn’t a Domme. The setting for this book worked out pretty well, as I used my love of horses and riding and the equestrian world in general to make her a professional three-day eventer who gets caught up in a scandal. Who suspends her from competition? None other than the man who showed her what it means to accept submission at the hands of a strong yet loving Dom. And you know those equestrians, they have all sorts of gear that lends itself to a BDSM relationship.
Then I decide I’d like to travel back in time again and want to write Marisa and Iain. As usual, I can’t make up my mind – it’s like trying to decide between the Brownie Sundae cake and the Italian pastries for dessert. Can’t I have them all?
So the debate continues – I may just have to flip a coin. I’d love your opinions. What do you think? Which would you rather read?