Let's rephrase things.
I am not close with my sister at all. My mother updates me on her life, my mother updates her on my life. I text her frequently and try and call on a regular basis, however that being said, I have received a grand total of three texts from her in the past 8 months.
My mother begged my fiance and I to have a wedding. We obliged.
When choosing a wedding party, the only person I explicitly asked to be a bridesmaid is a MOH. Every single other person I asked to be in the wedding in some capacity, depending on what they felt most comfortable doing, not necessarily be a bridesmaid. I understand that it can be too much for a person to help with, but there are other ways for them to be involved. To each and every person that I sent the invite to be in the wedding to, I said, "If you would like to be a bridesmaid instead of some other attendant, this is the dress that the MOH has picked out."
I have texted and called my sister relentlessly, and it took her four months and arm twisting from my mother to get her to respond to me. I received three texts: the first stating that she will be in the wedding but doesn't care what she is doing, the second stating that she will not wear a dress (to which I said that is fine, there are plenty of other ways to be just as involved or more involved in the wedding, I offered for her to officiate), and the third saying that she had to go to work. She hasn't gotten back in touch with me for TWO MONTHS. Several people of varying rolls in the wedding party, MIL, and my mother have begged her to get in touch with me and she still hasn't for unsited reasons.
My mother, in the meantime, told her she would be a bridesmaid. I DID NOT tell her that. I figured, given her personality, she would choose to have some other roll regardless. My mother told her she would be a bridesmaid because 1., my fiance's sisters are bridesmaids and, according to my mother, I cannot have his sisters and not my own; and 2., "that is what women do in a wedding" according to my mother. It will cause family drama if my sister is not a bridesmaid. It may very well cause more family drama if she is a bridesmaid that does not dress the part.
I have three questions:
1. How best do I approach things with my mother?
2. Because of how uncommunicative she has been, and how hellacious it would be to have her theoretically in the wedding party but refusing to talk to people, is it unfair to rescind my invitation? It has been SIX MONTHS of this.
3. If she does come around and confirm an interest in the wedding and start acting like she'd genuinely like to be involved, due to the fact that the extent of my knowledge from my sister is that she is willing to be in the wedding (NOT necessarily a bridesmaid) AND that she has staunchly refused to get in touch with me regarding ANYTHING AT ALL, how unfair is it for me to say she has three choices: dress and bridesmaid, her own outfit and a roll she decides, or not involved?
So... I am not close with my sister AT ALL. I wouldn't go so far as to call her estranged, but the only reason we ever talk is because we are siblings, not because we get along in any way, shape, or form. My mother twisted my arm into asking her to be in my wedding. I have an amazing relationship with my fiance's two sisters, so asked them to be in the wedding as well. Neither of which cared what exactly they did, but I really want both of them to be bridesmaids. They both immediately said yes and jumped right on board to helping plan. It took three months of practically harassing my sister to get a response out of her. She said she wanted to be in it, but didn't care what. I said great, the more the merrier, here's a link to the dress I am thinking about for bridesmaids.
Here's where it gets tricky.
My sister has recently come out as gender fluid. The very first thing she said was, "Well, I will be in it, but I won't wear a dress." I said no, please wear a dress. I never got a response, and haven't heard from her since that, and that was a month ago. My mother has said that if my sister is not a bridesmaid, the soon-to-be sister-in-laws cannot be bridesmaids. If she was a brother, my mother would have absolutely no problem with her not being in the bridal party because tradition states it is composed of women. If I was close with my sister I would try and come up with other things for her to wear. However, because I am not close with her and honestly don't care if she is even there, I do not want to go out of my way to accommodate her. I tried coming up with a different role for her, but again, my mother said that if she is not a bridesmaid, his sisters cannot be bridesmaids. I want to give my sister the ultimatum that she needs to wear a dress and be a bridesmaid, come up with her own other role in the wedding to be involved, or not be involved. I know that this will upset my mother, though.
Am I being unfair and harsh? What do I do about my mother? Advice?