If a tenant isn't paying rent and there lease is expired does this make it easier to kick them out?                        

I know your post is dated, but I have started looking at other comparable comps in the areas, using Zillow, Redfin, and the "Rent Estimator" on Bigger Pockets, etc.

For example, gives me $20,000 for down payment at 5% interest to be paid back by xxxx date. 

No one really cares about the closing time besides you the seller, and holding and closing costs can add up quickly decreasing your estimated net profit if the closing date keeps getting pushed. 

If you are not aware of what the rules are in your area, make sure it is specified in the offer in writing.I am not sure what the rules are in your state, so I might do something like this exampleBuyer shall inspect the property on (Date or between this Date and that Date. )  and shall have 3 days to accept the property, request repairs or cancel.In CA if any new  information is discovered and the buyer wishes to back out they have 3 days after the discovery to back out and get a full refund.

Being east of dahlia is also less desireable.  12 days on market hardly seems like cause to give up the sale... would have been nearly impossible to sell by Oct 1 with the list date...

Lots of steps, dates and procedures to follow.First, I would get up to date on what this tenant did right and wrong. 

I had a ticket and then transferred it to my business partner because I had a partners meeting scheduled for the same dates for my W-2 job.  

I have tried to reason with her but she refuses to leave even after her lease expired.

Tell them the offer is there with an end date and state that they seem to be having problems getting an offer to stick due to the condition of the building and the price.