Thanks for taking the time to provide such detail and substance.

There are professional predators in our world, just like there are professional tenants, that are out there to do harm.

NOT UNDER THE INFLUENCE: I am not now under the influence of alcohol or any other mind-altering substance, nor am I taking medication that would cloud my judgment or make me unable to think clearly. ________ 20.

(I'm pretty sure he has a substance abuse issue)If he were to quit claim the house to her so she had 100% ownership would that raise any red flags with the title or potentially interfere with my deal when we go to close?

If you default it goes into collections and harms your credit.

First floor has sent many abusive foul texts, but no overt threats to harm us.  

Try googling the term "house hacking" and you will understand.I meant no harm and sincerely do hope you use the resources on BP to better yourself and your investing career.

If they actually took time to read the substance, I think they will realize I'm not trying to shun people or discourage questions/posting.

However; I don't see what the harm would be, unless some type of preference was given. 

But there's no harm being in a good to very good investment.