If you did you would be simply sitting back and waiting at this point with no concerns.

But there are things such as minor repairs (update a pipe on a radiator etc).As for why more than 6 units a year = simply to have passive income so we can take care of our kids, my parents and leave grandkids with something.

As the leasee, I dont see how you gain any advantage over simply owning it in your personal name

I had an inherited tenant simply open the units main breaker and flip the switch.

A few places I simply say ' no animals' 

Do I simply need to write it on the purchase contract?

You would not need the additional income so would simply fold it back into your funds.   

I do get a little suspicious of Sellers who seem too keen to give attractive seller-financing terms - suggesting that: they win either way!

In these cases, you win some, lose some. 

For your bookkeeper you simply need to make a note on the invoice.