Oh didn't see these until now, great addition! Spending time together with pinkie will have a whole different meaning later on.
Seems these S-Links are getting longer, but seems appropriate at this point since it really fleshes out her dilemma.
As for how this will continue, one thought did occur to mind. At this point twilight seems so stressed that in order to talk to her again, one needs to use bimbo magic on her. Doesn't have to change her appearance or speech pattern, but she just feels somehow more relaxed easy going. So as an idea
----------------------------------
S-Link 5: Twilight is not in the library, but hiding somewhere different in the school to even get away from player, tantrum ensues.
S-Link 6: A very short conversation, where she's back in the library, but doesn't want to talk (ashamed of her actions?)
At that point when meeting her again in the library, one will only get ''She won't meet your gaze, her face buried in the books'' repeated until more bimbo magic is casted.
S-Link 7: When she sees you again she apologizes, somehow feeling better and reflected upon her actions.
- From that point on the player could make the choice that changing her was wrong and proceed the game without any further changes as the mental positiveness subsides with time.
----------------------------------
But again just suggestions, not sure if you already have a definite story route in mind.