Eventually the court should allow the eviction when/if they show no cooperation..

It is legally (in most states) for damages only.I agree whole heartedly in the suggestion that you could wave all fees if the renter cooperates and a new tenant is available for the date they vacate.

If she cooperates through all of this and the buyers do their final walk through and she is still there (I'm sure she will have a great heartbreaking excuse), you are now getting sued for breach of contract because you stated the place would be vacant.

While I'd never buy a super expensive car (I have a long ago paid-for 2008 Mini Cooper S that's fast, fun and perfect for me), I bought a pretty expensive house but I can walk everywhere, can rent my basement apartment for 3/4 of my mortgage, and love my pretty, convenient, city neighborhood.

Seller has been fully cooperative up to this point and will be receiving HAFA funds of $10,000 at closing.

Well done reaching $500,000 members imagine now sharing $1.00 from every member as an investment to create a syndicated operation of pro-members  for everone to "tap"into as a vetted fund -- a financial reserve to do single-family, multi-family, commercial properties-- since there is strength in numbers as a cooperative AKA as a pooled investment for even more growth in doing real estate transactions for years 2016 to 2030.This would eliminate private lenders, hard money lenders, angel investors or banks (I so dispise banks and their non-best practices) the reality is similar to an "acre of diamonds" where wealth is in your back yard (see my post in innovative strategies) to convert non-members into pro members...just saying

I believe the current tenant will be cooperative since she has rented from me for 5 years without issues.

I would let her stay one more month but can I ask her a favor to cooperate with me to show the house to prospective new tenants?

Naturally, we first try to schedule a time with the tenant, but if there is no cooperation or response, we serve notice and come and fix the issue.  

If you attack them over their entire housekeeping skills, they'll be less likely to be cooperative, in my experience.