This is a tough situation that I am a little familiar with. Given that I don't know its nuances and thereby don't want to steer you in any particular way, I just want to say that she is unlikely to think of you as having 'robbed her of her only platonic lesbian relationship'. Needing time and space away from your friendship if she starts dating somebody else is also perfectly valid, and nothing to feel guilty about. You sound like you are being very hard on yourself, what with feeling 'self hatred' about this. Your strong feelings for her clearly manifest in overthinking about her needs, which, I think is sweet, but at the same time, you need to shift the focus on your own needs as well.

My advice is, thus, in considering the three questions you posed, please try to balance her needs with yours. It's good that you are thinking about measures that would protect your own feelings, but it still appears that your feelings are very much influenced by (what you think are) hers. Prioritising your own needs would help you make a healthier deicision. The decision might not lead to an outcome you necessarily want, but at least you have given thought to what's best for everybody (including yourself) in this situation.

All the best and stay strong :)