No one knows for sure (that's willing to speak in public about that at least) but there haven't been soft openings; aka, pulling guests off the street; since New Fantasy Land opened in 2014. I can't see them going back to that method now but I also never say never.
Guardians did have a paid
D23 preview that was open to anyone with a paid membership, and quick sign up skills. So look at that maybe, if you don't qualify via another method.