I would also budget for increased cost of goods/services in the future.

They want a two year lease, no last month's rent, and a discount off the premium price I probably could achieve with more time on market. 

If you have an understanding of real estate and think you can get better results growing your retirement savings in that asset class, then a self-directed IRA or Solo 401(k) is a means to do that.All investments are made in the name of the plan, all expenses come from the plan, and all return accrues to the plan.There are several different plan types and service models available.  

It just depends on where you are looking and what returns you are trying to achieve. 

Their customer service/responsiveness during setup was a little lacking, but it's been smooth sailing since.

That does not include debt service, but does include taxes, insurance, advertising, lost rent to to vacancy or non-payment, legal expenses, accounting expenses, capital expenses (roofs, furnaces, etc), and property management.   

Do you recommend buying these lists from lead services that provide the addresses for absentees, etc?

Another weirdness that you may or may not face...many of the homes were continually having big wet spots appear in/on the slabs, hundreds of people, were calling leak detection services, thinking an underground plumbing leak was causing these mystery wet spots.

I have visions to achieve .

I.e. the smaller the space the high price per square foot you can achieve (and thus increase the buildings return).