If your landlord knew about the dog and did nothing, this gives you permission to have it -as his behavior becomes a waiver of any type of rule against having a dog.Now, you could take a chance you'll get away with getting a second dog, in the event he notices the second dog and doesn't object.But, any problems with dishwashers and anything else, are completely separate.  

I hope you put your agreement in writing.Just for information: If you accept rent late, your behavior waives your right to any late fees or ability to enforce rent due on time.You can re-establish your deadline for rent, by giving notice in writing with 30 days notice.  

You seem like a good guy, and sometimes us good guys can't fathom such behavior as tenants moving back in unannounced.

I didn't monitor any of my tenants until/if I got a complaint from another tenant or I just happened to observe or hear some behavior that I needed to give them a warning about.So, in my case, since I lived in the same building, if they were throwing a loud party, I'd usually see or hear it.  

Once you have put this behind you, a few years latter your investment will be fine.Two Priorities:(1) Replace the tenant, with whatever method that works and is available to you(2) Replace the PM, or self manageOnce you have a plan for these, write it down and execute your steps.Now; for the bad behavior and how to recoup your damages - may not be that simple.

Another is because when a landlord accepts rent late, his behavior effectively changes the due date.  

I would be worried that this would be discriminatory behavior, but it is probably OK since it is focused on the income.  

It took and displayed side by side pictures and an estimated cost to bring the until back to rent ready.  

Because of that past behavior, they know how to play the game better now. 

Why else would would you attempt to justify such bad behavior?