Honestly, I had no idea Rosie Perez had been a choreographer, thanks for letting me. That's fabulous! Then you got it. There's your Rosie.
What I got from Rosie's ethnicity is that she is from Latin descent, just obviously not any kind of stereotype that Mae attaches to "Spanish people." Plus, I think there's a joke in that "Spanish" really means that you're from Spain, nothing more. Either way, I agree with WannaBe re Rosie being played by a Latina.
"Some people can thrive and bloom living life in a living room, that's perfect for some people of one hundred and five. But I at least gotta try, when I think of all the sights that I gotta see, all the places I gotta play, all the things that I gotta be at"