If the tenants are under a lease, you have to honor the lease until it expires.

The contract has expired due to the buyer's lender not being able to perform on schedule and we have to decide if this property is a "keeper" or if we sign another extension and "ring the register".   

Instead of using an open-ended question, give them specific choices:Dear Tenant, Your lease is set to expire December 15th.

I dont know what it says about moving into one one the units , but in regular circumstances i believe it states that you must offer a new lease to the existing tenant when their is expiring?

If the lease expired, the tenant will convert to a month-to-month.

To complicate further, the rate lock on my loan expires 10/18 - I think it’s $9/day to hold the rate - I’m not paying and I’ll have to ask the seller to pay - I want the property but this feels like a warning.

Then you can mail or cold call or both.Other cheap or free methods are driving for dollars, craigslist, Realtors, FSBO sites, expired listings, foreclosure sites and bandit signs if allowed.If you have the funds you can use billboards, newspaper ads, other offline publications., TV commercials, radio ads, motivated seller website, SEO, pay per click/adwords, facebook, Linkedin, Youtube, and other forms of online advertising and boosted/promoted social media postings.Bottom line is consistency.

Check when the listing expires.

They are good for 2 years and after that they expire.  

Both tenants lease expired roughly three months after purchase.