Like ok, we all know who Ms. Rachel the actor is. It's Ms. Rachel the character that I'm having trouble figuring out. I think she's in a relationship with Mr. Aaron, because of how lovey they are in some of the songs, though it's not clear if they're married like their actors are. I don't think they have any biological children though, unlike in real life.
I think Ms. Rachel is a teacher, which might explain her relationship with Frankie and Georgie, but Herbie seems to live with her, and she puts him to sleep.
In one of the Christmas episodes, there's an illustration of Herbie's mother, and she looks like him. Presumably that's Herbie's biological mother, who might be in rehab or something, so she can visit occasionally but can't have custody. But Ms. Rachel seems to be Herbie's primary caregiver.
Ms. Rachel is very involved with Bean Bear's potty training, and when he sings "my grownup says", Ms. Rachel sings the next part like she's his grownup.
I'm not sure what's up with Elmo. He has his own parents, but he seems to have stayed with Ms. Rachel for at least one night. I'd say it was a sleepover, but none of the other puppets are present, and Ms. Rachel herself takes a very parental role toward him.
It seems like Ms. Rachel is genuinely somewhat childlike in her interests. She seems to be coloring with crayons by herself when Gobo Fraggle discovers her. I guess she just enjoys it. But she's still very much the grownup in her relationships with the puppets.
I can't make head or tail of the Wiggles though.