Regarding possible delays: I don't think there a reliable way to know unless something is announced by Disney. But your best bet might be to keep an eye on the weekly DL updates that are out there. And also keep an eye on
Youtube vlogs that keep an eye on construction and happenings. There is bound to updates from both of those sources through the winter.
You should be able to get access for everyone *on your DVC reservation*. Most contracts only have 1 or 2 "members/owners" on them. But benefits extend to anyone on the reservation traveling as a group or family. You are restricted by the capacity of the room, however. Unless I am totally missing something.
I've never been one to take a tour, so hopefully there are some experts out there. I know there are some recent threads about tours returning.