I'm guessing a big part of that "scheduling conflicts" has to do with the fact that no one had yet been cast as Spidey. That's sort of rediculous, honestly.
A show that big - with what has to be a LOT of staging and blocking - they should already be doing choreograhpy and at least pre-lim dress rehearsals.
So, now, there's a show, with no actors cast in the two lead parts. Oh, yeah, that'll last past the previews.