Just looking at zillow there are a TON of foreclosures in this area (it looks like it anyway).Your roof is leaking, the basement is getting water in it, you've got drop tile ceilings, the flooring is coming up, HVAC is old, Wood is rotting, Siding (at a min. needs paint, water heater is probably shot, and you've got peeling paint.

It's possible to add 50% or more to the main floor SF with the use of slab wings. 

And what if a section of flooring, or a countertop, or some other item in the house just needs a good clean instead of needing to be replaced?

Our strategy is to live in the basement level, rent out the main floor on a traditional lease and AirBnB the studio area.

A lot with a nice 2005 model home is much bettering positioned to produce revenue for many years than a lot occupied by a 1980 model that has an obsolete floor plan.

The problem is they are wanting to lay down laminate flooring all through the upstairs including the bedrooms where I was planning carpet.

@Douglas KrofcheckIf you have four separate units and wanted to install a central vacuum in each, it is possible each would need to be plumbed separately {for fire code reasons} - either back to a common mechanical room or within each unit - requiring a separate canister/motor to be installed for each.While a central vacuum would be a nice perk, I doubt it would be cost effective - it would likely be cheaper to finish all the units with hard flooring (no carpets) and buy a $50 Bissell Power Force bagless vacuum for each unit.  

This is a single floor unit that includes 2 bedrooms, 2 full baths, washer, dryer, dishwasher, refrigerator, stove, garbage disposal and 2 car tandem garage.

How much does flooring, paint and cabinets usually add to the value of a property?

We're in the process of a duplex refinance after a new kitchen was put in, all new flooring and carpeting, new windows on building etc.