An agent that recently showed the property reached to stating that their client love the property but would like to know if the landlord would be okay with installing a gas line or gas stove either at their cost or landlord cost.

We had already paid him $43k (in installments; way too much for nothing).

am in the cleaning and restoration industry.ozone and chlorine dioxide and many other suggestions here might work but the most important thing is that you have to treat the source for it to work.A professional grade black light could have helped you find the source easier before your contractor painted and installed new flooring.If it is very strong odor  the proper way to do it is find source,treat,clean everything and then chlorine dioxide or ozone.

The plan is to make a quick purchase and refinance, installing a new well.

I try to not let a property get vacant or if it happens then I pay to remove the unit then re-install. 

There is no way I can install skylight 

An agent that recently showed the property reached to stating that their client love the property but would like to know if the landlord would be okay with installing a gas line or gas stove either at their cost or landlord cost.

These can range from credits for installing energy-efficient systems to rehabilitating historic properties.

I installed new floors and painted, and worked with my husband and a contractor to install new windows, rehab bathrooms, and build a deck.

However, you would need to consider the cost of installing a new in unit washer dryer set.