Since it is a joint debt, can we exclude it from the BK and continue making payments on it?
We want to keep her strong credit completely clean.
Is there any reason to close the joint account?
Maybe if it was a credit union. Many credit unions have voluntary security interests written in their credit card agreements that attach the credit account to one of their deposit accounts such as a checking or savings account. This tends to be more of a credit union thing and not so much with bank like Chase or Citi, so you would probably be ok there. However, you should always have a bankruptcy attorney review the credit account contracts or agreements you signed off on as this would be a contract issue.
You also mentioned you want to keep your wife's credit strong since she is not filing bankruptcy. To do this, you would want to take her off any joint credit accounts she is on with you including any authorized user accounts.
Bankruptcy is a powerful tool and can be used to wipe out lots of debt. However, bankruptcy can get complex quickly and bankruptcy can have hidden red flags if one does not know the bankruptcy laws. I suggest you consult with a bankruptcy attorney so you know your options. Many of us offer free consultations.
You should sit down with a Bankruptcy attorney who should analyze your whole situation and answer any questions you might have.
Setoff is a contract issue. The answers to your other questions as best given during a telephone consultation regarding all of your facts and circumstances.
Take her off all accounts if you want to keep her credit strong.