Has anyone ever found out or have source of why this episode had the Fosse-esque dancing and costumes for a play set in the old west?

It's driving me bananas.

When Jerry introduces the three of them he says, "The Broadway Goldrush Twins", so I think that's the sign that they realized it didn't match what came before in the episode.

They may have been shooting for a very sophisticated number: Peggy Lee had recorded the song and the composer, Cy Coleman, had done a couple recent Broadway shows and some songs Sinatra recorded.

I always marvelled that Sylvia's character knew hardly any English, then a couple weeks later she could sing one tongue twister after another.

When Jerry introduces the three of them he says, "The Broadway Goldrush Twins", so I think that's the sign that they realized it didn't match what came before in the episode.

They may have been shooting for a very sophisticated number: Peggy Lee had recorded the song and the composer, Cy Coleman, had done a couple recent Broadway shows and some songs Sinatra recorded.

I always marvelled that Sylvia's character knew hardly any English, then a couple weeks later she could sing one tongue twister after another.

After reading your comment, I will conclude that the play went on as usual but the Broadway Gold rush twins were in addition to the play. I too was amazed that Sylvia's character sung perfect english in both the auditions and as one of the twins. Thank you for your answer.

After reading your comment, I will conclude that the play went on as usual but the Broadway Gold rush twins were in addition to the play. I too was amazed that Sylvia's character sung perfect english in both the auditions and as one of the twins.
I like Laura, but I always thought they should have just given Sylvia the part, instead of inventing the twins idea so they could both star. It feels like they did this to spare Laura's ego, and Rob from sleeping on the couch for a few weeks.

I guess it was done in part because of Sylvia's difficulty with English, and there was never a statement that she was actually better than Laura, more on a par with her. But I got the impression Laura got the lead every year, so I just thought it would be nice to give someone else a chance to shine.