I disembarked my men from my ships on foreign lands; is there an way to get them back on my ships? I can not enter an foreign harbour (i am at war withthe country).
Click the army, and right-click on one of your fleets in a neighbouring sea-zone. Assuming the fleet has a sufficient transport capacity the soldiers will move to the sea-zone and embark the ships.
I am playing the duchy of Munster and my heir is a woman. If I arrange a marriage will I only get an heir from her if it's a matrilineal marriage? Because I can only seem to get courtiers to agree to that, which reduces my prestige.
Yes.
Not quite; you'll still get an heir from a normal marriage, but he will not be of your dynasty. Meaning if he inherits, game over.