If you’re set on a duplex with minimal rehab, an investor focused agent should have a strong network of contractors who can give you quick quotes, so you don’t wind up with any pricey surprises.

Population and economic growth, strong tourism, proximity to other New England cities.

He strongly discouraged adding a backwater preventer bc he said he's seen it make things worse.

Rather than concentrate on the initial cash flow, concentrate your effort on markets that have indicators of strong rent growth.  

It should be pretty accurate - high level data sites are not always going to be perfect, but should always be directionally correct and AirDNA has a pretty strong track record. 

I'm not sure why not - one of the great parts about real estate investing is that you can build a team around you for aspects you aren't as strong at or simply want to delegate to someone/expert and do the others yourself - look up "Core 4" for example - where you can have an agent, lender, manager, contractor all at once for your investments and can theoretically just let them do all the interactive work

If you’ve got strong tenant demand, proximity to top employers, or even access to public transit, you’re laying a solid foundation.

It's going to offer Strong economic growth, Appreciation (especially in DFW), Tax advantages (no state income tax), and a Growing population, including infrastructure and amenities. 

Principal Paydown:  Cash Flow:  Tax Benefits: Savings from depreciation and interest deductions.For a deal to make sense, at least three of these components—home appreciation, cash flow, and principal paydown—need to be strong.

As someone else had mentioned, the prospect for appreciation should be a strong consideration.