I would recommend considering conventional financing until you reach Fannie Mae's limit of 10 properties, then consider either a portfolio loan, and start your race to 10 again, or look at DSCR at that time. 

What service/provider might you recommend.

Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

I highly recommend the coaching.

BiggerPockets also has a calculator to analyze deals, and I highly recommend you start this as soon as possible, even if you are not ready to buy.

That said, I highly recommend speaking with a local professional in the DFW area to get insights tailored to your specific goals.

Are there any resources that you'd recommend?

Ask any asset protection attorney, and they will recommend WY, NV or DE as best states to use.

@Wiley Hood to be honest, with all the new regulations around documentation for cost segregation that has come out, I recommend having a professional do them.

Having a long-term rental while living abroad is do-able.Flipping houses while abroad, in my opinion, more difficult, especially if its your first go around with real estate.I would recommend taking a flight and staying in the area for a week and inspect the neighborhoods and make connections.You can reach out to @Elenis Camargo who has a PM company in Jacksonville.Best of luck though.