That would be a helpful addition to your plan as you would further reduce your cost of living.Also don’t forget from that $600 you are planning on getting in cash flow you have taxes, insurance, maintenance, capex, and vacancy to consider.With two homes, you may want to keep that extra $20k as an emergency fund rather than spending it on a third property and then be left with no emergency funds.

Since you are doing new construction I would suggest making them private enough where guest have minimal interaction with each other.

You indeed have to spend that much money.

Raising your credit score will get you far better rates personally as well as with private lenders for your LLC. 

Always ask tenants to check to make sure it is locked.Another disadvantage is that you have to change the batteries regularly.Another disadvantage is you have to spend quite some time programming the locks and tracking the code3.

I spend so much time finding the 'right' properties across multiple markets on Zillow before I even evaluate in my buy box.

The client can distribute proceeds through a private agreement without involving the title.

Also, the idea separating them is so you don't accidentally spend them and then no way to pay it back when the time comes.Some states if you don't refund the security deposit within X amount of days, the penality is that you will have to pay back the security deposit x2. 

In our still relatively limited experience, seller financiers are usually looking to get a higher asking price in exchange for the favor of the private loan. 

Could be the best money you spend on the deal!