No, it's not though. Buffy (I suspect very deliberately) used the exact same language for scenario 3 - she just let him get it over with. Yet you easily concede that 3 was rape.
2) A woman is asleep but her new partner fancies sex. She is awoken and kind of goes along with his early advances (cuddling) but as soon as his hands wander, she pushes them off. He continues and continues despite her protests that she's not really interested, and she knows from past experience that if she doesn't comply he will insist on waking her up fully, putting the light on and berating her for rejecting him. Maybe the discussion will go on for hours and she has to give a presentation tomorrow. So, she just lets him get it over with, feeling awful about the whole thing.
3) A woman is asleep but her new partner fancies sex. She is awoken and kind of goes along with his early advances (cuddling) but as soon as his hands wander, she pushes them off. He continues, and won't take no for an answer, using his weight to hold her down and penetrate her. So, she just lets him get it over with, feeling awful about the whole thing.
Why is it ok in your eyes to emotionally bully a woman into sex, awaken her, sleep deprive her, berate her? Until she just "let's him get it over with." That is not consent.