If I dealt in SFH I'm sure more potential renters would be concerned with kitchen-size (I deal 100% in multi-family properties) but there's no doubt storage space is coveted in SFH as well. 

The neighboring buildings house a sheet metal fabrication shop and a truck accessory business.Given the factory/manufacturing character of the neighborhood, the opportunity for a normal tenant seems nil.

Try to find couches, chairs, barstools, rugs, towels, accessories that will fit most styles of homes (whites, beiges, etc).

The sister also wants to install SS appliances and upgrade the lighting accessories in the home at her cost.

The technical term for that is called an Accessory Dwelling Unit.

Signs shall not be placed on the wall of a residential building or an accessory structure.

If you put in a kitchen this could be considered an Accessory Dwelling Unit.

Miscellaneous bath kit for towel bars,  bath accessories installed 200.  

I would be very careful of this option of buying a home with  the plan to rent out a finished basement (mother-in-law or accessory apartment) and then move out and rent both the top and bottom. 

Here is where we are getting conflicting information and worried about everything going smoothly.We are buying a single family residence that has an accessory dwelling downtown where it is quite common for the old school mother-in-law cottage to be in the back.