Before you buy anything, I would search "Wholesaling" here and you'll spend the next couple weeks getting to know who has been here a while, has a reputation, and you'll find TONS of info.  

What you can spend?

I have to ask, since you buy low, spend some money and appraise high ... are you guys purposely using the BFRR strategy, or did this just kind of come about?

The only property tax discounts in Mecklenburg county that I am aware of are for the elderly low income households (65+) and/or disabled veterans and that only applies to their primary residence.  

The key to marketing to probate estate PR's is to understand, identify and recognize the major issues that turn from being a market price seller to a motivated seller.I suggest you spend an hour or two and just list the scenarios, then use these triggers in your marketing message as the reason people contact you.

However, I think If I spend between $6k and $7k to put central air in it, it will match comps in the area up to $75k or so and have a huge upgrade.

Welcome to the community brother, I've found that the more I can spend time on the site and hear all the encouraging stories, I become more and more motivated in doing deals.

Id just say spend the $ on the location..... youll be thankful you did 10yrs from now. 

I can't spend my day chasing around investors to their favorite coffee or lunch spots.

I'd spend your time and energy on an arm's length deal.