The Baptism Ceremony is not how actual Catholics perform it. The Godfather is not the one who holds the child, the Mother does. The Godfather just observes, nothing more.
Maura Tierney (Abby Lockhart) & Hassan Johnson (Darnell Thibeaux) also worked together on episode 4.5, Waiting for the Knock (2012), of The Good Wife (2009) as Maddie Hayward & Gavin Wells respectively.