Note there is room in this timelime for Paddock to meet up with his money laundering/gun-running/terrorist buddies for several days at a time away from Marilou, if indeed that happened, both in the first two weeks in August and then again beginning Sept 14 in LV.
I agree he certainly must have had other contacts that were aware of his plans, if not actual real time support in the massacre, but the "gun running" angle is harder for me to accept. He would have not have been limited to use weapons tied to his name, or limited himself to weapons bought from stores that sell to hobbyists. I realize that made them all trace back to him, for cover, but he didn't even have the most powerful arms a citizen could buy for a mission like this, since it appears he mostly used AR-15's. Just my thoughts, and enjoying your posts.