On paper we were slightly in the red but much of that is due to one-year expenses/repairs & allowable transportation costs to get up to the property for work days ourselves. 

Are there any potential red flags I should be aware of?

Every interaction with them has raised red flags. 

Most agencies are slow to process paperwork, have a lot of bureaucratic red tape, and it is difficult to get them to respond to inquiries.

That is a red flag to me but I find it hard to believe that a business with 4.8 stars on so many reviews and A+ BBB rating could be a scam.

If you can't close fast enough or has too much red tape, then you lose the deal to others.

Don't see any major red flags here, so long as you are comfortable in the low income space.

The red flag here for me would be the willingness to overpay when they’re not bidding against anyone.

Real estate for the last four years was betting on red or black but the ball was fixed to win as it was nearly impossible to lose.

Also, real builders/experienced developers will often have a true technician, i.e. a civil engineer, architect, real estate attorney et al at least glance at the property info to make sure there are no major red flags.