It's an inferior product and if moisture becomes an issue, you'll have to redo the whole thing.You can usually save a lot of money on lumber by buying from a building supply store (lumberyard) instead of Home Depot.  

I can also purchase information pamphlets on mold/moisture and lead-based paint that I am required (by federal law) to give to tenants upon move in.

Should I pay the 5k+ out of pocket to remove all flooring/drywall etc to remove all material where moisture has been present?  

Yeah, I’m a fan of the old folk...they’re gentle on rentals for the most part vs the younger renters.  

Is maintain moisture area a home that diffcult?

It has been amazing & maintenance free.I recently went to a trade show & they had several booths with much the same product we used so its getting popular & some of them are now applied/sprayed on as a 2-3inch thick walk-on insulating foam impervious to moisture.

I'm thinking wood rot from moisture as the brick threshold and roof runoff funnel water towards that area.

As far as flooring Laminates do not hold up that well to moisture (ie water spills, milk spills etc.)

These areas are prone to excess moisture.

But this is because the people advising me know that I have history in construction and I can spot major issues in the foundation and structure or if the house has a moisture problem.