The listing agent said that financing shouldn't be a problem, and she gave me the number to a local commercial lender that she said had done numerous loans at 10% down.I called the lender early last week and gave him the basic information and he said it shouldn't be a problem, but that he'd have to get preliminary approval first.

I am investing in Ohio for the obvious reasons (low price, high rental demand, equity potential, ETC) but I am investigating moving to Arizona (outside of Phoenix) , outside of Atlanta or somewhere in Texas (San Antonio or Austin area).  

If you are looking to develop investigate opportunity zones. 

Does anyone have any experience with a similar situation, any insight into the challenges that may come up, or any advice for putting together a preliminary written proposal detailing plans for the zoning board (the property is not inspected or purchased yet, but when I asked the board if the zoning would allow the conversion they asked for a written proposal). 

Investigate and take into account the "health" of the home owners association and hire inspector for the whole building, not just condo.

Investigate and take into account the "health" of the home owners association and hire inspector for the whole building, not just condo.

how do you investigate a neighbourhood where you invest?

Without getting into the weeds here, we: review free preliminary application, proceed to tenant-paid credit/background check, proceed to lease and payment.

I just watched a video where they showed how they got a preliminary ARV in just a few minutes. 

If the answers to the above question are no, then I would suggest that you start with just doing some investigation based on the electrical bills of the rest of the units.