Because of cost, duplexes are are a better choice and compete well with SFH and or apartments. 4.  

Now I’m looking into the Detroit and Ohio areas (Toledo, Cincinnati, Cleveland, Columbus) since they seem to have growing populations and affordable properties under $200k as well.  

Localized knowledge for an agent or investor is needed to answer most of these questions.

Coaching or mentorship in real estate investing can allow you to collapse time and "skip to the front of the line" by leveraging the experience and knowledge of those who have already achieved success in the industry.

With all the measures they have, it's never been an issue to my knowledge and the neighbors would let me know in no uncertain terms, as they had a poorly managed STR in the neighborhood previously. 

Will look into seller concessions and gift funds to get better knowledge. 

20-25% I guess you have your reasons for the down payment discrepancy between citizens and non-citizens, haha, but it doesn't sit too well with me.

Here's an article with things to consider when selecting a cost segregation company.

(This includes character attacks as well.) 

The one you select really depends on your needs and bookkeepers preference.