You answered the main question I had when you replied that you received a final K-1.
From a tax perspective, this is key and any final gain or loss needs to be determined in the year of the final K-1.
Having said that, I strongly recommend you get yourself removed from the business checking account. Just because there may be some time and administrative inconveniences in doing so, you need to be off this account to protect yourself; and sooner rather than later.
*A reminder that posts in a forum such as this do not constitute tax advice.
Also keep in mind the date of replies, as tax law changes.
