Friend extremely jealous of my best friend

So I am a 16 years old gay guy and this year, I have met my new best friend. She is in most of my classes at school and she is lesbian (but wants to transition to male in the future.) So I have this other friend that has a crush on me since 2 years now, and she has asked me out twice, but I clearly told her in a polite way that I am not interested and that I am gay.

Her reaction was fine (although she tends to slip some homophobic insults sometimes by accident). Also, we were best friends before and we dated for about a week (I thought I was bisexual back then.) The problem is, I have told her recently that I feel like she is not as close to me as she used to, and told her honestly that I am now best friends with my new best friend that I made this year. (She asked me if I felt closer to my current best friend.) I tried to not hurt her feelings, and wanted to have this conversation with her and I finally had the courage to tell her that I don't feel as close to her.

Sorry if this is so long but here is the troubling part:
She tries to mimic my best friend! (And not just lightly.) The other day, she literally told me that if her religion told her otherwise, she would be a lesbian and transition to male. Now if what she says is real, I will be very supportive of her, but I doubt that what she said is honest since she told me right after that that she has a big crush on a guy in our year. (And I KNEW it was me.) She also constantly gives me very affectionate hugs and touched twice my legs when I was sitting in the lounge area of my school. (Not just slightly touching them, she was grabbing my legs and it was super awkward and made me feel SO uncomfortable!!!)

All of my friends tell me that she shouldn't be so touchy and she should stop imitating my best friend, but I don't know what to tell her because she can be pretty dramatic. Sorry for this rant.