You have yourself a very challenging battle here. My primary suggestion would be to make sure the overhangs on your structure go out as far as possible to limit the amount of water that will actually land on your slab (if this is even possible with your building). You could possibly have the...
Excellent progress. The excessive framing seems odd, but it's only a few extra bucks in wood and fasteners. Installing batt insulation is going to be a royal pain, unless you are doing blown-in or spray foam. At least mounting things to the walls should be easy once everything is done.
Also, it...
Very nice. It's definitely a struggle getting out there getting things built right now. It looks like you are over on the west side of the valley? I used to live in South Salt Lake.
The directions will tell you how large of gap those products can cover, but from the looks of those pictures I would definitely put backer rod in there. If you don't you'll be wasting a lot of product just to fill the depth of the gap.