I have some properties in mind that I think would work well (both short and long-term) but I don't have money for down payments.

there are many long and detailed threads on this company. 

I'm not having any luck selling it so I'm thinking of pivoting to a midterm and short term rental as a buddy of mine has had some success with his house in Paris Mountain and the 09 zip code in Greenville.

"Long Distance Real Estate Investing" by David Greene is a good options and will help with getting an idea of good markets all over the place, not just your own backyard. 

I have been listening to the bigger pockets podcasts for a very long time and have been in analysis paralysis for years.

As I move purchase price and terms around as we negotiate, at what cash flow amount would you pass on the deal?

@Bob RooksJWB does have a good reputation, have been in business a long time, and are vertically integrated.  

Sharing a kitchen probably isn't a big deal for a short term contractor.

Financial goals: Our current jobs provide for high-income but not a lot of time for active real-estate investing, so our strategy is long-term buy-and-hold with less headache properties.

You are better off getting a Principal and Interest loan since you would be in the low to mid 7s at that PPP term.