The basement is finished with a kitchen and separate entrance, which indicates to me a possible 3rd unit.  

Making the bathroom a focal point of your improvement is certainly a safe approach to making the lasting impression; and of course curb appearl; shutters, nice entrance door are always safe investments.

You can have the identical house (close, but not really identical) in the second block from the entrance to that subdivision and it may be valued at $300K, you can go 6 blocks further and the other may be valued at 10% less simply due to interior condition.

Financing would be 75%LTV with standard entrance/holding/exit costs....maybe a rehab loan as well through my portfolio lender.

The third is a single family home with the main entrance on the second level of the home - there is a large flight of stairs leading to it.As I'm trying to get my R.E. investing business off the ground, my first reaction is that I should follow the entire process through on all of these, if for no other reason than to get the experience. 

@Rod Smith my inclination would be to refi cashout as much as possible, AFTER I maxed out the rental value (i.e. find the amenities your competitors have: DW, GD, cleanup the entrance) then get something else.However with a sale and 1031, the Multis will give you the economy of scale that'll really let you get ahead.

For example, ceiling fans in the master bedroom and family room, improving the curb appeal and the front entrance area, fresh paint, etc. 

The homeowner mentioned they were thinking about moving into a one-level ranch as the main entrance in this house is on the bottom level so they have to go up stairs to get to the main living area.

Each "unit" should have its own entrance and essentially be separate from one another.  

I plan to do this by improving the cosmetics and functionality of the building (new windows, repairing fence outside, providing locked entrance door with intercom system, etc.)2.