The listing agent should be in control of the listing, with the informed consent of the homeowner. 

You should also reiterate that he is not to make ANY repairs or modifications to the property without consent.

I had actually had a new property under contract in 2018 that I let go because it became such a big argument and became clear without his consent, it wouldn't be a good experience.

“Seller will not enter into any new leases or extensions without written consent by buyer”So to get reimbursed for appraisals inspections etc, I would have to go to small claims court?

Often wholesalers pitch an off market property only to find out it has been on the market forever and is a real dud or it is listed and they are up charging the price without consent (false advertising). 

If I were to sign a year lease agreement with an owner before listing it on Airbnb, don't I need consent from the owner to bnb it out?

Borrower shall occupy, establish, and use the Property as Borrower’s principal residence within 60 days after the execution of this Security Instrument and shall continue to occupy the Property as Borrower’s principal residence for at least one year after the date of occupancy, unless Lender otherwise agrees in writing, which consent shall not be unreasonably withheld, or unless extenuating circumstances exist which are beyond Borrower’s control.Is this just boilerplate?

You need opt-in consent before sending a message.

From what I've read, I think sending out an automated mass text message to people who have not provided express written consent is illegal.

The moment you apply for a mortgage, that fact is sold by our trusted credit reporting agencies (TransUnion, Equifax, and Experian) to the entire world, so they can start spamming you with junk (one of our lobbying groups, AIME, is trying to make it illegal unless you explicitly give consent to TU, EF, and EP).