When the production was first being produced on Broadway, there had been some controversy about the name "Aunt Jemima" for that syrup...mainly because 'Jemima' used to be a popular name for a black woman. Part of the controversy also came from the depiction of a "mammy" to advertise the syrup. To avoid any possible problems, the producers of CATS decided to change the name from Jemima (Original London name) to Sillabub.
The name Sillabub is an actual name made up by T.S. Eliot (who wrote the poems which CATS is based on), whereas, Jemima was made up by Trevor Nunn. The name 'Sillabub' is supposed to be a mix meaning of silly and beelzebub (mischevious/a little devil). Out of all the productions of CATS around the world, Sillabub is used more often than Jemima. Although some productions have made each name into two different characters and included both characters in their cast, most productions have only one or the other. Essentially in these productions, aside from the name difference, the two characters are portrayed generally the same and do the same things within the show. I tend to like the name 'Sillabub' better than 'Jemima'.
Hope that helps.
~MsJ
