I would predict around 100-120 but this obviously depends on renovations.

I've already spent a few more thousand dollars than I predicted I would have needed to fix a few things.Like you said, having that cash reserve makes it so much easier to sleep at night!

For us, we use machine learning and big data to predict the ARV as close as possible, however, there are several factors that sometimes the data does not account for (distance to train tracks, traffic patterns, ratio from renters to owners) that can affect the ARV differently street to street.

I love military areas for stable tenant base, predictable rents due to BAH rates which you can google, and respectful tenants (I know there are always exceptions but the good far outway the bad. 

No one can predict the rate, but if you control the property then you can control the cash flow and value to some extent.

I've also noticed a lot of doomsday predictions about REI here and everywhere.

We are looking to get the house for $125,000 purchase price, with an estimated $80,000 renovation, and a predicted ARV value of $300,000.

Will the surrounding areas of Nashville continue to grow or is the growth period coming to a close? Which nearby towns do you expect to be "up and coming?" 

If we had bought a condo we would be limited to what the market rents dictate for that area.With that being said, it is better to get into the game and buy a condo if that is your only option for the amount you are pre-approved for.There actually is a new option to use the rental income from a permitted ADU to help you qualify for more by using the predicted future rents of that unit in a SFH.

@Sean KuhnI like fixed rate 15 or 30 year amort.While you plan on paying off the mortgages within the 5 years, things happen and 5 years is a long time to predict the future, but a very short time when there is a balloon hanging over your head.While nobody likes all the Fannie regs, the lower fixed rates are worth going after.There was a post at the National Real Estate Post, just today about how people would rather spend a night in jail, or gain 10 pounds than go through the mortgage process.http://thenationalrealestatepost.com/hilarious-mortgage-survey-is-very-revealing/?