These elements sent me back to the workplace where I know I don't have any business being, like where I am now.

Starting with the smaller unit mix is great because of the ability to finance them as residential purchases.

I've begun my direct marketing which has already produced a few promising leads and have been analyzing three properties a night to improve my ability to find a great deal.

Over diversifying is generally done by lazy investors who do not have conviction in their investment strategy or are confident in their ability to execute.I worked in investment management (non-real estate) for over 13 years.  

With your ability to put some sweat equity into your properties you are open to a few more opportunities.  

And plan on having the ability to obtain Post Construction Bonding for a variety of issues.I applaud and admire your competitive spirit!

If you are very confident in the Turnkey company's ability to manage save the 8-11K by purchasing on your own and bring them (or another group you feel comfortable about) to PM the unit. 

It's not just about getting the next deal, but about how the next deal might affect your ability to get the 10th house and so on..That said, I have an excellent mortgage broker which I've used on multiple deals.

As another poster suggested, if you are sure there is plenty of equity and you have the ability buy out the 1st. 

I believe if you rent it to your children for substantially under market you may lose your ability for certain tax benefits as an investment property.