Have a lengthy list of do an don'ts and explain that you run a tight business which is professional and thorough.

Probate is a notoriously lengthy, expensive, and stressful process.

After some time on the market and lowered rents, it finally rented for $850 on 3/10/23 (as of today, May rent is overdue).

@Joe Splitrock the owner probably got burned by a previous guest and felt compelled to try and protect themselves with a lengthy agreement. 

Thanks @Chris Adams I'm surprised I even got one reply on this lengthy post.

I'm thinking a vacation is long overdue.

However, even if they accept your claim, litigating this would be a lengthy process and I suspect they would have roeopen the foreclosure, file a QTA reforming the mortgage and redo the  sale. 

I hope this lengthy insight helps as this is what  I have learned thus far as a new investor and experienced agent.  

What an expensive and lengthy process it was.

Give them a lengthy heads up and risk turning good paying tenants into difficult tenants or wait until about 60 days out and leave them in a situation where they may be scrambling a bit to figure out their next step?