How far does the female MC can go at this update?
As far as I know, the last added content to Kate's story, came with update 0.50. Check the changelogs on page 1 of the present thread if you need details.
You will find "sex" in Kate's story now. Quite a lot, but it's just sadly inconsistant and totally lacks any reciprocity. It's always someone masturbating in someone else, or pleasing them then "the end". The only real exception to that being the sex with Alice, but even that is centered around her camshow.
How many girls can the female MC have sex with currently?
It depends on what you actually call "F on F" sex but :
Alice, Julia, Lien, Veronica (but it's a sad joke of a scene),
Sophia (but it's a sad joke of a scene),
Angela (a little less a sad joke, this time, but it includes NTR with zero sharing),
Ann (but to have it, it means Max gains controle points over the villa, or it is interrupted if you don't want that), a lot of
Karen but with NTR heavily included.