Which do you think would be easier, getting the Obamacare to stop the auto deduct from her account or contacting the utility companies?
Next, the car insurance should not be a consideration. She should have that paid up for the whole year to take advantage of the discount offered for doing so.
With the utility bills all that needs to be done is wait for the bill in the mail and then send a check.
Are you sure you are not trying to make this one more difficult than it really is?
Canceling the Obamacare auto-pay should be easier than closing her checking account. My checking account is the default funds source for various online billings that I use on a fairly frequent basis. Closing it would require me to switch every one of those over to use the new checking account.