Honestly, I think the family dynamics are a bit flipped for this group:
Shirou is the Cooking/Cleaning Mama, no questions there.
Rin is the Bread Winner/Tester of those who'd dare try and date her love interests
Saber is the Stern Father/Tester of those who'd dare try and date her kids
Sakura, if she's part of this, is the Hug Mom-ster.
They've essentially split the parenting roles in half so that each individual can help in raising Ritsuka.
Oh probably, but Rin's still likely the best at it, to her chagrin. She has the greatest amount of observed... talent in the light novel, Shirou as stated before is trying to catch up, Saber has no clue what do, and Sakura's too messed up to truly learn what do.