So due to the fact that I am not there to visually see the property up close, it would probably be a good idea to have a contractor give me a quote before I close on the property? 

You can take screen captures. so a visual identity is on record.

Patch walls and replace broken screens as necessary, and fix or replace small things like cover plates for light switches and wall sockets, light fixtures, doorknobs and faucet handles.AppearanceMake the duplex as visually appealing as possible by increasing its curb appeal, the term used to describe how the residence looks from the outside.

One thing I am still seeking is a visual blueprint to run off of.

This one had a spooky feeling basement, but NOTHING visually unusual... until I looked at the photos. 

We are visual "creatures" and the professional just has a way of sprucing things up for us!

I think painting them white will have a significant visual impact on the house, allowing us to maximize rents.

The changes are very visually uncomfortable for me.

I find it hard to visualize what you are calling the "back wall".In your original post you referred to a top wall, a left wall, and a bottom wall.

depends on the demographics.If its a retirement neighborhood, lots of elderly people some may find it a tripping hazard or a pain for walkers, wheel chairs etc...Down here in south Florida many older folks would not buy two story homes because of having to trek up and down, and we have lots of older folks.Sometimes the elevation difference can be partially minimized visually by using creative threshold transition pieces.