There may be a way for you to get around this by setting up an entity with someone who is of age and is capable to consent to contractual obligations.

And this only happened if they got consent from both the seller and buyer.

If there is no contract to purchase the property, you and anyone who represents you cannot conduct any rehabs without written consent from the current owner. 

I'm gonna see if I can ask for the contingency that the seller gives her consent for the inspector to discuss the report with me.

I have been documenting as much as possible, taking care to communicate in writing, either via paper or email/text and any in-person conversations with a witness – to not take any chances with this tenant as I suspect he is video-recording in-person conversations without our consent. 

Government operates based upon the "consent of the of the governed"...that's us. 

You must get written consent when you do this from the leaving tenant.   

As stated above, if the contractor hired the architect without your knowledge or consent, I would argue that those costs fall on him or her. 

Most like she isn't allowed to add an occupant without consent of the landlord. 

How would I know the Airbnb pm company or anybody else isn't opening his or her own account and listing my property to earn money separately without my consent.