The character of Mammy Watkins was originally written for and offered to Esther Rolle. This would have been a reunion for Rolle who co-starred with Bea Arthur from 1972 to 1973 on Maude. Rolle, however, declined the role.
Mammy Watkins' age is never revealed, but it is implied that she was like a second mother to Blanche. Ruby Dee and Rue McClanahan were less than 12 years apart in age, so it is possible that Dee was made up to look older so she could play Mammy the same way Estelle Getty was to portray her character, Sophia.
Sophia sets Dorothy up with a matchmaker (which upsets Dorothy). Bea Arthur originated the role of Yente the Matchmaker in the original Broadway production of Fiddler on the Roof.
Mammy reveals that Big Daddy's actual first name is Curtis.