I am finding it a bit challenging to keep track of all the URLs like HOA, Electric, Gas, Solar, Taxes, etc. in one place. 

If they have a separate gas and electric meter your generally in pretty good shape.

I told him BS, but he called the electric company to have the power cut for "safety reasons" without asking on a Friday Afternoon. 

Owner said they made substantial repairs including new wiring, new electrical panel, all new insultation and repair of any charred areas. 

If you're thinking of turning the shed into its own unit, it would require some serious upgrades—like adding a separate electrical panel, sewer, and water connections.

Modern finishes, Washer and dryer and refrigerator.3bed/2bath minimum is preferred in the Texas Market.If you can add 2 car garage, that will make it more desirable and attach more buyers.All the best

Agreed, last deal I had in Jersey city was lost due to really bad plumbing and electrical issues, on a older mixed use building. 

I can do all the basic things like lawn maintenance, snow removal, painting etc, and some electrical and plumbing.

Will this new wall be required to have electrical service added per code?  

Be aware of the costs as you'd need plumbing (water and sewer), electric and possibly a separate meter to the new unit.