Landlords are NOT allowed to ask the tenant:(1) What the nature of the disability is for which the animal is attributed(2) For proof of training(3) For any documentation regarding the need for the animal (unlike ESAs)So, if my understanding is accurate, what is prevent an unscrupulous tenant from showing up with a "service animal" for which I cannot ask for documentation of its training, the disability, or any validation from the ADA?

Both on the contractors end because they know they will continue to get business, and from the management teams end because you won't know what the bill was supposed to be so they can upcharge again.Since you have already been in contact with your tenants, I would call the tenant for whom the $750 bill was attributed to and see what kind of plumbing issue they had. 

I attributed it to the heaven rain fall we were getting at the time.

I personally love living in a big urban area and enjoying all of the attributes of it(walkability, mass transit, culture, diversity, incredible restaurant and nightlife options, architecture, pro sports, entertainment), but I realize that's not for everyone.  

(B) A restriction on the size and attributes of the junior accessory dwelling unit that conforms with this section.(4) Require a permitted junior accessory dwelling unit to be constructed within the walls of the proposed or existing single-family residence.(5) Require a permitted junior accessory dwelling to include a separate entrance from the main entrance to the proposed or existing single-family residence.(6) Require the permitted junior accessory dwelling unit to include an efficiency kitchen, which shall include all of the following:(A) A cooking facility with appliances.

We did not think we were going to have to record a quitclaim deed with the county to show a change in ownership, but now with the property tax credit attributed to my mother-in-law, it seems like we need to do something.

And how do you know whether to attribute performance  to 1) the property/condition , 2) the tenant being rough on the property 3) cost of doing business, normal occuranceoff the top of my head I'm thinking:Days to close out an issueTimeliness in responding to issuesAnnual/quarterly repair expenses# of repair request per yearOr even how do you know whether or not your getting better at landlording /property management over time?

You have to use the whole population not a subset in your calculations.China population 1,396,164,036 Covid 19 cases 80,754 = .00578% deaths in China attributed to Covid 19 cases 3,136 = .00022%https://www.livepopulation.com...I'd be a lot more worried about a 'quake in SeattleWashington’s 30-year earthquake drill for the ‘Big One’: Order studies.

Since the property seems to have had deferred maintenance what can I attribute to that?  

At least in my area and after doing some research with the city; appears that if any house is currently being used as a Multifamily (3+ units)....or can have documented use (such as a utility bill) of being used as a multifamily in the last 2 years, then it  can continue to be used as a multifamily.However, without these attributes, then the town ordinance does not allow for multifamily and everything in town is zoned as single family (SFR).