So, funny enough after I rehired all the staff and vehicles, I played for about 2 hours, built a bunch of new stuff, got my baggage working correctly and was working to build a new runway and then CRASH. I realized I had not saved since rehiring. So I do not know 100% if the rehires all stuck or not. After the crash I started a new airport as that one, being my first one, was not one I wanted to continue anyway.
I did rehire a few new contractors, I believe I saved the game at a point so the staff are still gone. I did switch branches to experimental and opened that file, all my staff didn’t show back up, but again, I think I saved it after they all disappeared (when I exited the game I think I hit Yes to the save prompt by accident).
Ill update if I see this again.