My question is, what are the chances of mold developing either on the underside of the laminate, on the subfloor or both?

While it keeps the building very warm, I suspect I have shorted the life of the sheathing dramatically and may eventually have problems with mould in the wall assembly.Closed cell directly on the underside of the roof deck or inside face of the exterior walls allows you to pack a lot of R-value into a 2x4 cavity (theoretically R22).  

The roof didn't leak, but air escaping from inside the house condensed on the underside of the roof and rotted the SIP.

@Masa Asao First, congrats on having a tenant that cleans the underside of their toilet rim!

He fixed some dry rot around the toilet, but didn't check the underside carefully enough (from the crawl space) and left a small spot of mold.

So far we've taken all the wood off the top (underside) of the porch and replaced it with tongue and grove pine and replaced the single ugly exterior light with 3 brushed steel pot lights attached to a dimmer.

I was taught from an inspector that the black on the underside of the roof is a stain from previous mold and if the right condition arise again, the mold would come back if not treated.

(I don't know what to call it exactly, and frankly I don't want to think about it too much because it makes me gag) in the empty areas of the underside of the toilet, not where the water goes, just the empty parts of the structure.

I like the idea of nailing to the underside of the joist.

The bracket he used attaches to the underside of the eaves and curves above the roof so no cables running over or in the gutters.