I think of her as bi, and that’s how I’ve had her describe herself (See this and this).
I don’t subscribe to the idea that “bi” means only attracted to men and women. It means attracted to more than one gender, and I think of Helen as being someone who could be (and has been) attracted to quite a variety of people across the gender spectrum. So technically, she could be called pansexual. But if she was trying to quickly explain her identity to someone (especially someone who isn’t aware of most queer vocabulary) “bi” is the most easily understood term.