Its rare a show has such different Universes and exists in 3 different worlds in a way. Usually a show moves a network and there are changes or during a shows run (like Happy Days , Family Matters) that make changes in Universe as a soft reboot at removing characters like they never existed. But there is a show that completely changed universes 3 times it appears.
Back in 1967 , Carol Burnett introduced the sketch variety show "Carol Burnett Show" which would go on to run 11 seasons and become one of the longest running variety shows of the 1970's. Even with its final season and ratings so low , CBS was very loyal to Carol Burnett and the impact she had created on the network and TV industry. They wanted a 12th season but by then Burnett was burned out of doing a weekly series and decided against another season.
During the mid 1970's cast member Vicki Lawrence would do a character that she would be identified with her entire life. As "Thelma Harper" she emerged in the sketches called "My Family" where as Mama she would at times cut down her own children. The children in these numerous sketches were slowly introduced and this Universe we will call...
Mama's Family : The Carol Burnett Universe -
In this universe Mama Harper is still alive in the mid/late 1970's and a widow. Her husband Carl had died years earlier and its revealed he died on the toilet. Mama is more mean in this universe and will constantly berate and put her daughter Eunice and son-in-law Ed Higgins down. There is very little good to Mama in this Universe as she cuts down her children quick with little reward at times.
Thelma in the CB Universe has 5 children. Larry an artist and graphic designer (Alan Alda) , Phillip a writer and film producer in LA (Roddy McDowell) , and Jack a local hardware store worker (Tommy Smothers). Ellen (Betty White) and Eunice (Carol Burnett) completed the family. Through the sketches each son is put down for their career and direction in life they have done while only Ellen is spared this anger. As she is considered the good child.
As time passes in the CB Universe ; Thelma Harper grows older and has to live with her daughter she constantly puts down in Eunice and her husband Ed. This puts a strain on things as by the end of the CB Universe run Ed Higgins has finally divorced and left Eunice (Harvey Korman who played Ed had left the series and they wrote his character out).
Eunice (played by Carol Burnett) was a sad character who once dreamed of being a big actress among other dreams ; married dim witted Ed after high school and quickly had 2 children. Billy Ray Higgins and Bubba Ray Higgins. Both are never seen but Bubba its claimed is a troubled child in school growing up. Jack its claimed has a wife that is possibly cheating and has 2 children (not named).
Mama's Family : The Eunice Universe -
This Universe was introduced a couple years after Carol Burnett & Company (a summer series that continued the CB Universe version and ended it in 1979) arrived in 1982. This one shot TV movie introduced a whole new Universe and a number of changes happened.
Thelma Harper was still a widow who lost her husband Carl a few years after 1955. She was now the mother of 3 children : Phillip (played by Ken Berry) who was a successful writer and later film producer , Ellen and Eunice. Nothing changed for the other characters at all as the years passed in the TV movie.
Phillip would leave for NYC to work as a writer , much to Mama's anger at this and trying to stop him. Eunice had big dreams of being an actress but settled and married dim witted Ed Higgins out of high school. They had 2 children Billy and Bubba. Later its revealed Bubba would run off as Phillip would help Eunice pay for a detective to try and find him. Also Ed would leave her like the CB Universe.
Thelma Harper in this Universe was still angry and would cut her children down. But she also had moments of kindness as she wanted to help her grand son come home . Also at the end of the Eunice Universe version Mama Harper dies. As her children unite after her funeral at her house at the end.
Mama's Family : Modern Universe
In this Universe introduced after the successful TV Movie , NBC rebooted everything. This was the biggest reboot of the entire concept.
Thelma Harper was a widow who lost her husband after he died in bathroom years earlier. She had 3 children : Vinton (A local hardware/locksmith) , Ellen and Eunice. Living with Thelma in this new Universe was her sister Fran (Rue McClanahan) a would be writer. Fran its hinted never married and had moved in after Carl's death to help her sister.
Another change is Phillip is removed from the Modern Universe completely as well as Jack and Larry. Vinton is the only son and has 2 children Buzz and Sonja. All 3 were allowed to move in as Vinton's wife had left him. Leaving them homeless so Thelma who loved her son and grand kids allowed this. Much to her sisters dismay.
Speaking of Thelma Harper ; her character now was a sarcastic old lady who was tough but had her loving moments. She practiced tough love for her children and grand kids. But gone was the mean old lady completely from the CB Universe. The Modern era Mama Harper ruled the roost and let her children know if something she didn't like. But showed she cared for them.
Eunice and Ed had one child now as well. Gone was Billy , instead Bubba Ray was mentioned as their only son and a troubled child. This was the 1st of the Modern Universe that NBC introduced in 1982. There would be no more changes to this universe beyond the small reboot that happened a few years later. Where Bubba Higgins was introduced on TV and Thelma's younger best friend Iola Bolin. With Buzz and Sonja moving away to live with their mother.
But over all the series had 3 distinct Universes that had changes like a comic book universe as time happened.
CB Universe
Eunice Universe
Modern Universe