There are actually several "concept" recordings of Star Wars musicals out there (basically midi files recorded at home). There is one for Empire Strikes Back that's been around for years. That first article was either severely misinformed or a hoax as there has been no mention of Twlya Tharpe choreographing anything for Broadway other than the Dylan piece. The mention of Michael Flately being cast as Vader and the Riverdancing Storm Trooper number should have tipped you off.
As for the Chuck Wagner clip, that was actually from a demo recorded back in 1978 (?) for a proposed Broadway musical of Star Wars composed by none other than Charles Strouse which obviously never went beyond a reading.
I think it's safe to assume Star Wars will not be hitting Broadway any time in the near future and probably not in George Lucas's lifetime.
"What can you expect from a bunch of seitan worshippers?" - Reginald Tresilian