I don't think that Bowie would take up his role again, even if it be a broadway show, I don't really know, but I think it seems unlikely, maybe they have to contact him for permission, if they want to use the songs etc. Or even possibly requesting envolvement artisically for more songs? Who knows? But I'm not sure he would star again no matter how much everyone wants him too, and if it was a show they are referring to, I'm sure everyone would love him to return to the role but I sadly can't see it. Just as much as I can't see anyone else playing Jareth, Bowie made him his own, the character was practically part of Bowie's past personas. But I guess that is something I would have to get used to, if I really wish something else to happen with it, i don't mind the broadway show, even if I never get to see it! It's a film version of the story I don't think would go down well, it obviously doesnt need a remake, and a sequel would spoil the imaginations of all that have made the story their own- its like them saying "this is really what should happen." When there are so many different interpretations.
If they do do a show, I'm guessing it would be a remake, not a sequel or preqeuel. I don't think they are referring to the comics, fans have known about them for some time, so that isn't hush hush. But then again, even if this broadway idea never kicks off, I'm sure something will surface out of all of this, one day, they have generated alot of excitement.