>>1 okay, where do I even start? I'm bisexual. I am sexually attracted to women. How scary am I? I'm as harmless as the next straight girl. By best friend is a straight girl who fully supports me and encourages my sexuality and "awwws" whenever I talk about girls, which is the best, nicest thing that any bi/les girl could ever want in a best friend. That being said, could you please calm down and be supportive? If anything that's what Anna would love most from you.
Let's use a comparison shall we? Do you ever see those boys that are just playfully grabby? I've seen straight guys, best friends grope each other. It happens. It's for laughs and not for anything sexual. If it makes you uncomfortable, then just say so! "Please don't do that to me, I don't like it." or even "I'm really, really ticklish so don't". Simple. Don't treat Anna differently just because she might be gay. She's just another human being, treat her as such okay?
As for your friend Jane, if her sister is a lesbian then she's probably fine with other lesbians I'd assume, and it's her choice whether or not she wants to return Anna's possible feelings for her or not. And so what if Anna likes Jane, she sounds more like she's loved her for awhile. Now I can see how that could possibly create drama but feelings and emotions are just there and they can affect our personal relationships which is normal no matter the sexuality.
lol let me tell you something. My tumblr is 98% lesbian material. Please don't judge people's tumblrs. They're PERSONAL BLOGS. They don't have to be "normal". If you don't like it then unfollow her. I'm not a bad person for having a yuri themed blog, she probably isn't either.
Hopefully this helps you better understand things. Good luck :3