Some good questions, and some questions that don’t align with the facts as we’ve been told. For instance, reports are that there were 23 guns in the hotel room, but you asked how he got 42 guns into the room. As I understand it, 23 were in the room and 19 were at his home in Mesquite, NV.
The lack of stamina argument is silly. Certainly Paddock was keyed up with adrenalin and had the stamina to bump fire several weapons for ten minutes. The question I have is a little different. He wasn’t using tracers and the trajectory of his fire was downward, at an oblique angle, and he was firing at night from 400 to 500 yards away. How did he know where his bullets were landing, and how did he put so many shots in the concert area? By all accounts he had no military training, and a few degrees error in any direction means that he misses, yet he apparently stayed on target from beginning to end. This does not make sense.
Point 2, additional shooter at a lower level. As far as I can see no other windows are broken out other than the one from which the shooter fired. That would seem to exclude a shooter from any other floor.
Been to many large hotels and casinos. Park next to the doors exiting the garage to the elevators. Pull your own bags off your vehicle. Load into a cart usually found near the elevators or go get one before you open your car or truck.
Load three or four are bags. Someone asks why you have a lot of luggage. I’m part of the convention, show, band, etc. Put do not disturb sign on the door.
Rinse and repeat. Go back to gager and park in open spot.