I am close to starting construction on 2 metal building shells which we will finish out the interior over time. The metal buildings will be red iron / weld up. My location is Central Texas; hot humid climate. I have declined the use of spray foam because of several reasons.

spraying foam onto the interior side of the metal cladding sometimes voids the warranty from the metal building company.
in my case, the foam would spray over plumbing rough in, other cases spray over elec and mechanical. I don't like this is covered with foam and repair means disrupting the seal of the foam and spraying more foam after.
I don't like its performance in a fire. Yes it does have retardants but if the fire is hot enough it would melt, outgas and be a danger to people in the building.

If you do use spray foam, use 1-2" of closed cell. Open cell is not enough of an insulator on a West facing wall for heat gain and seems to pass heat straight through to the frame walls.
For me, I am planning to use mineral wool batts. I am also having the metal building erector install a standard house wrap between steel structure and exterior metal panels.
A few things to ask:

there is not much of an air gap between the panels and the house wrap, but the main point of the air gap is to allow any condensation to drip down between the house wrap and the panels. Is there a good way to create a fire barrier at this location? How and with what material?
Is there a way to maintain an air barrier at the house wrap instead of a vapor barrier? In hot humid climates a vapor barrier can sometimes cause condensation on the inside of the wrap causing mold inside the home. I am more familiar with wood construction. In metal is there a different application for the house wrap / fire barrier / moisture barrier?