You are going to privately lend an investor on this deal and you will offer them 85%/100% at 10.99%. 

Have you ever made an insurance claim?

I am using a title company and will have title insurance. 

I find that selling owner user commercial property with 20% down and owner financing the balance is quite easy and usually results in at least a few quick offers.  

Everyone seems to talk about including the costs of the new mortgage, taxes, insurance, maintenance & capital reserves, and the vacancy projections when looking at realistic cashflow, which we already do for all the properties in our rental portfolio.But we, like many, cant find properties that are making any cashflow sense right now.

Additionally, I offer my clients my experience as an investor as well as my network in order to help them accomplish their goals.

But, if things go well. so far, i've heard from my brother that the owners of the property we are aiming for, are being difficult and wanted us to make the offer before looking inside the physically looking inside both the units of the duplex. 

Can anybody offer insight for which things to be mindful of as part of our due diligence before purchase?

Consider highlighting any special features to stand out, and maybe even offer a move-in discount to attract tenants quickly.

Texas has a lot to offer, and it sounds like you’re on the right track!