I think the plan for Unforgettable is to allow Jim to have relationships with all of the women, not just Kayleigh. And since most players are men, I think they found that more enticing than playing a female protagonist. For Unforgettable, I don't think Kayleigh will be having sex with other men, it'll just be Jim having sex with various women depending on the choices made.
As for the training, I don't know too much about the club. I'm not even sure if Jim has a role in that game. Heck, I'm not even sure if the script was finalized. I would imagine that all options are still on the table as the dev team takes a wait and see approach to the reception of Corrupting and then to Unforgettable. But if you really like Kayleigh and female protagonist stories I would encourage you to let the Dev know here, on discord, and on Patreon because he's always been responsive to my questions and thoughts.