Preferably no more than 30 minutes from a good size city or town.

I own a 7 Family in the down town portion of Norwich that does well.

The host, Justin Kivel, breaks down the terms and underwriting in a way that is easy to digest and in bite size videos.

The study identifies with forensic engineering detail the immediate Bonus Depreciation 5, 7 and 15-year personal property class lives qualifying portions of a building that are normally buried in 27.5 year residential or 39 year commercial categories.The Cost Segregation Study was performed on the Asset Depreciation Range (ADR) and is based on a 40% tax bracket for State and Federal Taxes.

Often even without self-sustainability test, these FHA buyers were finding themselves in nicer properties with their portion of the payment being less than rent and they OWNED the property (so they got to enjoy tax benefits, appreciation etc.). 

Agreed with @Ashish Acharya point above.One thing to add, bonus depreciation is available for used property placed in service after 9/27/17, however it is does not apply to the portion where the taxpayer previously had a depreciable interest.

Family details is important so they know what bedroom sizes will work and won't.

But you'd always want to talk to the city right away (or county) and find out the development standards for the zoning that the lot is in (what are the setbacks, height limit, min lot size, etc).

What are the pros/cons of a portion of the monthly rental amount being applied to the final purchase price, vs. no credit of monthly rent towards eventual price?

The smaller the loan size, the more you should consider paying a few points at closing so you are not looking to do another refi any time soon.