First, Ms Schneirer did not offer olam habo to anyone. She tried to help others the best way she could. Some rabonim, like Chofetz Chaim (*) and Beltzer Rebbe, favored her efforts, many others did not and made it not easy for her. Be realistic – she is not supervising BY brand min hashmayim, the way McDonalds Corp does with their franchise. So, a school claiming BY label is run by specific people the way they see fit, within certain limits. OOT BYs are different from in-town ones, for example. And what is “asur by gedolim” in one, would be OK in others.
So, the main lesson from Ms Schneirer is that educating girls is important. To clarify the problem she was solving: boys went to schools that were paid for by relatively affluent Yidden and poor ones got included. As there were no established schools for girls, rich Jews used tutors and poor ones were left ignoramas. So, maybe apply the same approach today. Find a small group of girl parents who can afford paying tuition and want companionship of several other girls and start your own classes. Find a kollel yungerman who will teach them chumash and Rashi, his wife to teach them davening and middos, enroll online to get English and Maths. This will not be a full-blown BY with entertainment, but you can always enhance it later, maybe apply for Jewish Federation grants to help you or find a Rav who will be willing to give high quality classes a couple of times a week. This is way better that sitting around, complaining about out-of-control school admins. Think what lessons you want your children to learn.