I feel some of them were out of nowhere, such as Est going away (nothing like that was implied in any supports) and I can't tell if it's a FE2 reference or not.
Arran dying was foreshadowed in supports as he was terminally ill and determined to win this war before dying.
Luke's thing was basically while a knight, he was doing so on his terms (hence a playboy leaning).
I do wish some of these were forshadowed better.