KnittingMama, I am sorry your dd is having a tough year. I would wonder about a few things - first, do you think any of her unhappiness with school is coming from wishing she was homeschooled like her brother? I would want to know more about the situation with not having friends at school. There can be 1 million different reasons for that - ranging from things within your dd's control, things with your dd that she can't control, and things with the other kids that are beyond her control. Whatever is going on with that, I'd want to know and understand. It could be as simple as she's happy the way things are and doesn't need a close friend, but the hiding in the bathroom and general unhappiness with school combined with not having a friend would nudge me to consider what might be going on beyond simply being a bored gifted student.
DD is starting to go down the same path DS did in 1st grade, and if she remains on the same trajectory, it will be a disaster.
This, too, would nudge me to consider is there more to this than just a bored gifted student? I did a quick look back at your posts re your ds and his year of school previous to homeschool. It sounds like he had some similar issues with school and that there may be something else at play than just boredom.