Dom: I saw that Rose bunked with Victoire. Dom may have been a teensy bit jealous, I suppose. But now that Victoire is married and Rose is living with Lily, I think that Dom may try reaching out to Rose more. They are cousins after all, and are quite close in age.
Amber: Rose may know Amber from when Rose was Head Girl. Amber was the Slytherin prefect. I think that Amber may have idolized Rose because she was smart and because Amber wanted her job.