You clearly dont know what a lesbian is.
Lesbians dont want, do or like dicks. Katja is only lesbian until you allow guys, but if you say you dont like the living sperm dispensers she is the only true lesbian you can get, starting as virgin and staying loyal.
Lena could be the second lesbian, since i dont know her planned questline (if any) i dont know about her past or what she does outside school...dunno if i confuse lera and lina here, but i think its lera who plays with guys around your family house.
Albina is a whore, anushka is a slut, julia and natasha had guys before and depending on the route natasha can end as breeding stock, lariska is a bitch, first you save her, then you start a relationship and THEN she goes dickhunting and even gets pregnant, anya starts with a stupid boyfriend and had more guys then braincells, sonja is a cumslut and wrong, you can have sex with mira the townwhore.
I think what you want is the cook in the gopnic hangout in the residence part of the city.
However, the only 100% pure lesbian in this game is my protagonist since she dont needs an option to disable dick content to avoid, slap, kick or burn guys to death.
Katja is a good first step in the right direction (the jerk/ivan thing still needs a change or removal), i really hope more girls get the option to disable guys...and we need more virgins (dont repeat it nutlick, just compare your statistics with the amount of girls in the game, there need to be more virgins if you want it realistic) with the option to keep guys away.