To address the flashing, I cut a 1/4" groove in the siding for the 1/4 lip on the flashing, which I will fill with a urethane sealant & then nail the vertical below the groove, with sealant behind that.
Added joist hangers to the rafters at the subfacia. Added a stud, and finished out the paneling behind the press to a depth of 58". Going to add another 2x10 plank for the platform to make it deep enough to easily walk on & move the heavy equipment around, which will even it out with the end panel depth.
The universal foam I bought from Home Depot is supposed to expand to up to 1", to seal the gap in the corrugation valleys. I don't think it's going to happen - I've left it unwrapped for over 24 hours, and 1/2 of it is just as uneven thickness as it was wrapped
Gutter will sit along these lines