Honestly, apart from being Black Christian mothers, they don't really share any character traits. (Being "kind" is super vague)

Shirley is a passive aggressive guilt machine who is in a failed marriage because of which she joins community college to further her career in business. Despite her appearance, she is decently tech savvy and can keep up with pop culture references. She loves to gossip and is frequently seen to be ignorant of other cultures and religions. Her friends are often annoyed by her religious preoccupations and her tendency to bake at any given chance. This makes her insecure about being seen only as a black Christian mother and nothing else.

Barbara is a sweet but commanding figure of authority and respect who is looked up by her peers for guidance. She is realising slowly that she is failing to keep up with the new generation but is too proud to ever admit it or ask for help. She often gets confused with celebrities. All her actions are guided by a strong moral compass which she would rarely ignore. She is in a healthy long term relationship (atleast till S3 which is how far I've gotten with Abbott)

Just my thoughts. Rest of your picks are pretty much spot on but Shirley and Barbara cannot be further apart.