When we flip there we usually have to tear up the floors from the top side to do whatever repairs are necessary to get a clean termite/moisture inspection, then pray we get it sold before the letter expires.  

How does this brand of flooring hold up overtime in bathrooms? 

Exterior will need $3-$4k, then once vacancies start, we will gut ceilings and address moisture issue in attic with venting, insulation, etc..

Tenant agrees to allow Landlord timely access to premises to do maintenance and repair.Tenant will notify Landlord in a timely manner of any damages or problems as they arise, including damages caused by Tenant, malfunction of appliances or fixtures, and water/moisture leaks and spots.Tenant will take care of the premises, keeping them clean and clear of debris.In your case, the tenant may have been oblivious to what was happening, or saw it and didn't care to tell you.

Did you need to add any underlayment or moisture barrier to that product?

Basements have too much moisture and if a pipe leaks that carpet is toast.

They stick a specialized camera up the flue (if it's unlined) and determine if you have water penetration through the chimney.

As a career I am a professional penetration tester.

it comes with a 25 year residential warranty, and it will hold up to moisture and water spills way better than a typical laminate.  

.)- Mold/moisture present in the basement / fungal growth - Exposed wires / wire defects all over the place- Major foundation cracking in the basementI don't know much about construction so I would be paying someone to fix all of this.