"Moisture and dirt are entering the basement near the stairwell""Additional support columns/beams lack visible hardward securing them into place"Engineer noted there is no structural component dug below freezing level on any of these supports which would need to be done to get the foundation supports to code"Signs of water penetration noted on the basement walls"Picture showing proximity of nextdoor house"The soil slopes towards the foundation, or is flat, and must be corrected to prevent water from finding its way to the foundation" (This is the side of the house with the failing retention wall in the basement and has extremely limited access) The engineer recommended potentially just paving cement between the houses to seal it and recommended against a french drain as installing it would go below the level of the foundation already.  

I am worried that the odor has penetrated one of the commercial units (a bank). 

I presume you have considered other common issues with basement units such as moisture, separate entrance, etc.

Carl,As a fellow property manager and real estate broker I think there are some key item to look for:Any moisture on the windows, around toilets, under sinks.

Water penetrated the lower unit for days and days.

There is an old axiom in marketing: "Concentration, penetration, domination."

Note; paper underlayment will be cheapest, but it's cheap for a good reason, and it's not its robust life expectancy...The strapping you mentioned is a slight added cost, but if done properly (vents at the eve/drip edge and ridge), can actually help lower inside attic or top-floor temperatures, as you now have an "air gap" to help alleviate some of the penetrating UV heat, as well as helping to drain and dry condensation that WILL form on the backside of a metal sheathing.

Premium vinyl or laminated flooring.Laminated is a bit restricted to low moisture.

I haven't heard of anything quite like you're describing, but in general I always tell people to use a higher sheen whenever moisture is present.

I wouldn't say one if better than the other, and both are effected by water/drainage/moisture, but the issues to look for are different for both.