Spoiler: theory
Ok i reread the rebellion arc and i think we will meet Marion at Normandi.
AND i think i know who killed the father of Sarah.
This is kate who did it. by order of Veilen. Because Veilen know about his future and wanted to have Sarah with him because of these visions. and beside Kate came to see Sarah rather quickly after the death of the father. Her trip with Belmont take a week before she reach Rosanna. and he make more sense when i think about it. (Marion are the one who engaged Veilen)
If i am right
I will gladly beat the shit out of her in front of the whole company (it would be very dramatic to see Caleb and Ephraim reaction). And spared her life only because she had value to the company. if i had this choice in the warrior road.