Ahhh, I get you now so the books are entirely different stories not sequels per say.
So Book One completely deals with this storyline?
I know a group of people exist on here that really hate playing as female MC. I don't know how big that group is but it may limit your player base for that particular story.
That being said, if you do keep the same MC you'd be entering Mass Effect territory with romance options. Trying to balance choices from the previous game with new options.
I know that's only the side stuff but some of us do get right into the romance side of things.
All that said i'm not much of a writer when it comes to stories so the only advice I can give with regards to what happens next is don't plan it just yet.
We're still a ways off this reaching it's end point so see where the wind takes you when you see the end in sight. Maybe you have an idea where to take our MC and the gang from here on another adventure or another part of the story and those characters involved caught interest and you want to run with them. Could see the vampires side of things or any of the institutions.
You are creating an entire world here with some great lore, you could literally go anywhere with Book Two.
Right! Book One's entire story is the mystery of Lisa's murder and getting to who did it. The resolution of the murder opens up a piece of the bigger world.
From there, I have a bunch of ideas -- some going forward as Kylie/Kyle as they learn more about some other facet of supernatural life (the Convocation, the Bureau, vampires, fae, the Cult of the Void, the [REDACTED UNTIL CHAPTER 3 RELEASE], etc). Some involve playing as another character (Lisa pre-death, Tara pre-Lisa-death, what Jodi's been up to, etc). And some even taking place in a part of the world that would reference what happened in Baltimore, but not involve
any of those characters.
The "Mass Effect" problem has indeed crossed my mind (despite me being unable to actually play the games because of my motion sickness. *Sob*) -- I think that's a lot less of a problem since you don't have to be particularly monogamous with anybody. Though I'm sure it could affect who you may accuse of murder...
Having a new protagonist would mean I'd have to still carry over some data, like Nelson's gender and romantic entanglements, but also means that the new MC wouldn't have to worry about that stuff as they pursue whatever girls are still alive for Book Two. I have a lot to think about, but I still have about 4 chapters in Book One to get through (it should be no more than seven, total).