Their loan origination fee and $1234 rate lock extension fee = a unknown surprise to me - other things are standard as you said.

It can often help to include unknown LTV and a purchase/transfer/sale date of 5-10+ years.

The appraisal part is unknown, and rents in the area (and demand) support a rate of $1100.   

I also think it is a good idea to minimize your taxes now, while positioning yourself the best you can for the future (where everything is an unknown).It certainly would not be a bad thing to also use your retirement accounts to invest in real estate (as long as you are very careful to follow the rules- avoid self-dealing!). 

That way your profit is unknown by the Owner/seller. 

I definitely added the term "hard metrics" and maybe that was my misinterpretation of the metrics used to analyze deals.I think you are right about the subjectivity of the numbers and about the unknown variable in a deal. 

This time I took photos of them breaking all the house rules-leaving 1.5 hrs late, extra guests, spilled liquids on the floor and some unknown substance staining the sheets, photos of a cigarette box, cigarette butts, cigarette ashes.

Yes, she is fine except her credit score and the unknown any eviction case. 

Are there any other ways to feel relatively safe you will not be hit with a big unknown lien once you buy?

I’ve had an inspection done before where things like the furnace or AC didn’t work (for an unknown reason) despite them being brand new.