I'm not sure of the exact timing of how it would all need to work....but thinking of a few options to consider:
a) drop the family off at WL or FW before you go to the airport to pick up the others...they can relax, walk around, have a beverage, play, etc. and then you and the later crew meet them there in time for HDDR.
b) have the family take WDW transportation to FW while you are going to the airport to pick up the others.
Options a and b eliminate the extra trip over to Pop, which is not really close to FW.
c) you drive yourself and the family to FW and have the latecomers take a cab there...meet them in the parking lot to stash their carryon luggage in your car before the show.
this (c) eliminates your trip back and forth to the airport, which will take at least an hour or maybe more, depending on if you are there waiting for the latecomers to arrive, if their plane is late, traffic, etc.
And I'm just thinking off the top of my head...since it is prepaid...better for at least some of the party to get to experience HDDR than none of you (if the travel and transport plans hit major snags and you are at the airport, your family is at Pop, and HDDR is starting... )