Tenant not paying rent prior to move out

[Christopher Munson]

I have a long term tenant in a SFH at $1766/mo that I contacted on November 8 to provide notice they would need to purchase the house or vacate by Feb 1. They were very interested in purchasing, and I gave him my mortgage broker's #, which he did contact. The tenant (male with Father cosigner, has wife and 2 teen kids living there) has good history other than occasional lateness (1 week), but always caught up with fees. They pay rent by depositing to my bank account by the 5th. At the time I contacted them, the Nov rent had been paid. Yesterday I checked the bank account to confirm Dec rent had been paid on time, but it had not, and the Nov rent check had bounced (which my bank never informed me of). I contacted them yesterday to find out what's going on and if they planned to move out or purchase. He told me they can't afford to purchase, they have to use their money for security on their new place, and they'll be out by Jan 1. In his mind, we have their security and last month, which should cover it. I explained what security deposit is for and that we did not collect last month rent at lease signing, and he needs to pay Nov and Dec rent Asap. He is offering to pay $1k this Friday and $1k two weeks later, and "go from there". He has a cosigner that had great income and credit 9 years ago. I told him I look forward to receiving the $1k this Friday and hearing confirmation of their move out date. I think my best option is to play nice, get what money I can through Jan 1, and then assess damages once they're out to decide if the damages are worth a small claims court suit against him and cosigner. If he fails on payments, is there any benefit to eviction notice assuming he follows through on move out by Jan 1? I think if I don't have payment and they're not out by Jan 1 (or scheduled reasonably close to that day), then I have to initiate eviction. Ideas from the landlord community?