This is why I felt the twist was nicely done and clearly planned for as already part of this scene. Even as just anime watchers I recall the questions arising from how long she held him for as well as her staring at her hand before changing her course of action.
It was nice tip off along with Armin noting the curiosity of it.
Yeah!
Yeah, I think it might have been around when he returns home with Mineva/Audrey.
As for the other, I don't think Lalah Sune is ever referenced in previous episodes, not that she would be since her connection comes from the original Gundam series.