The church that Mike & Molly get married in is the Triple Rock Baptist Church that is used in the Blues Brothers
Cleo King who plays Grandma sings 'Think' in the church whilst waiting for Molly which is sung by Aretha Franklin in the movie The Blues Brothers
The homeless man that Molly and her sister ask whether he has a cell phone is the writer for Mike and Molly, Mark Roberts.
Dave Allen plays Tom in this episode driving Molly and Victoria to the church. He also played a troubadour in Gilmore Girls which also starred Melissa Mccarthy.
The man who drives Molly and her sister to the church is character actor Dave "Gruber" Allen. He was part of the 90's Comedy Central Comedy The Higgins Boys and Gruber with David Anthony Higgens who portrays Harry in this episode.