Two months ago, I chatted with Janusz Kaminski, Spielberg's DP on WSS. He wouldn't divulge a lot of details, but he basically said the new film is VERY VERY similar to the original movie, but with a great cast who can really sing the songs themselves.
So I have no proof but expect there will once again be no Somewhere Ballet in the new film. Hell, even the new Broadway revival couldn't find a need for it.