You are looking to create the biggest spread possible so shopping around for the best rate and terms should be a priority.

In my roughly 14 yrs of owning rental properties, your biggest risk is not in payment of rent but actual tenant.  

If he titles the house in mom's name by gift (no gift tax this year due to unified credit) , she has lived there for the right amount of time, can she exclude the gain entirely under Internal Revenue Code Sec. 121?

If they are low revenue and high maintenance or not...

The only thing that would be different is that Proper covers revenue loss + all the bells and whistles  I feel I don't need for 2x the cost - squatters/bed bugs.Any input on this from more experienced STR investors or others with insurance backgrounds please?

You want to target homes/markets where %15-20 of the purchase price in yearly revenue in possible.

I think I am learning that I probably should have said rent-ready and not turnkey, but I think you have answered the subtle question I was asking which is, is it possibly worthwhile to invest in properties that give you only one type of revenue (paying down the mortgage) and maybe don’t give back the cash immediately for the next investment?  

I work in their retirement plan services business, and the biggest regret I hear from folks in their 40s-60s is that they didn't start saving early on in retirement plans.

Generate the most revenue for them.2.

I experience behavior like this every day.You may not like what I have to say.It seems that the biggest problem was how you managed the process.