Their lease technically ends on Sep 30, 2018 and I was given verbal notice today that they will be leaving when their lease ends.

You want a bunch of security behind the note so if the buyer runs the property into the ground and it becomes semi or non-performing you have some options and recourse.Now if I was on the buyer side no way would I agree to such terms from the seller unless partially on some of them if the property was way under market.You have to find a balance where the buyer is happy and you are happy doing the deal.

Looking to buy my first property and will have my parents as non-occupying co-signers (I will be occupying the home though).

That ends up around $3,000 dollars to net around $10,000 dollars.Unless your mailing probates (and pretty much only that niche), 300 isn't going to get it done (or you'd just have to be extremely lucky or in the perfect non-competitive market).

There were 2 separate individual (non-connected) houses on the lot.

I had an idea in the back of my head that i shouldn't be bothering people at their own homes as it can cause physical/verbal aggression ( people are crazy ). 

The rest of the non-$$$$ don't guarantee that those that will live in the houses, will have the same opinion of those non-$$$. 

They determined that the unit was a legal, non-compliant unit.  

1. walk through inspection with them present to compare to move-in inspection and noticr of non-complaint behavior if any .

We verbally agreed to a "Sale Price".