Using a real current example on one of my investments, the home in the ~$750K range leaves me with an average mortgage of about~$3500.

I've heard https://www.rentometer.com/ a few times on the BP podcasts, although I will say that the estimated rent for my current property is about $200 higher than the range it gave me.

Expect rates in the 8.5% - 10.5% range. 

Your best bet is either find a lender who specializes in that range such as auto/boat/motorcycle, etc. or you have to go to the usual advice of a local credit union or bank that will lend from their own books. 

Or is a lawyer sufficient?

Most of them have their strategy narrowed down - IE - single family vs multi, basic price range, Hold vs Flip, how much renovation they are willing to do. 

@Kaylea Bienek google fha self sufficiency test if looking to buy a 2 or 3 unit.

All of this will add up pretty quickly so you want to make sure that you are in a position to move forward instead of finally finding a home and being told you are $5,000 short on being able to close.3) You can look into using the BRRRR strategy.With $36,000 I would say that you will be in the price range of about $100,000 may be a little bit more.I think the BRRRR strategy would be the best option as it allows you to refinance and take your original investment (plus more if possible) and then start the process over again as opposed to having to save up another $36,000 to start over. 

More often than not, using neighborhood comps are more than sufficient for finding the ARV.

Taking a discount of that number for OKC is fair so maybe closer to the $35-60k range @Rick Imby mentioned.