I will only use my personal bank account for the property until the business bank account is setup.I assume this avoid the issue you are mentioning here? 

Dollar Stores often instead of renewing the lease get sucked away to developers promising to build them Dollar Plus stores with upgraded construction for slight rental increases.Especially is absolute NNN lease the DG could jump ship to a brand new building and avoid tons of TI costs they are on the hook for with older building ( parking lot, roof, A/C, etc.)Professional tenants with thousands of locations tend not to be dummies.

Primary $250,000 per spouse avoidance on capital gain.  

If you can afford a higher payment, a 15-year mortgage saves on interest over time.For the down payment, aim for at least 5%, but if you can put down 10-20%, you'll avoid PMI and could get a better rate.

Just have a few questions before we get to deep into the process:What are some common mistakes that can easily be avoided?

What I am getting at, is if it is worrisome, or avoidable, as even a good deal(see scenario above) will raise DTI In that case, yes DSCR loans closed in an LLC will not report to personal credit and won't affect your DTI. 

-Transfer the property into an LLC – This may allow me to take ownership while potentially avoiding property tax reassessment, however this sounds like an involved process-Establish a living trust for my aunt and mother – The trust would specify that I inherit the property upon their passing and provide step up in cost basis but i'm worried that the living trust can be modified to have me removed (who knows what can happen) - My mother is somewhat volatile.I would like to live in the property and my mother will live in her second property with her husband. 

A smart, hard working person could use this info to avoid many costly mistakes and near replicate the process. 

One thing you might think of doing is having and promoting your own website to avoid the exhorbitant fees charged by the third party sites such as Expedia, Booking.com and Air BnB.  

It seems unlikely that he is avoiding you since he has been so consistent.