Can anyone please tell me where I might find a detailed checklist or task list of things to do just prior to a bank merger?

I don't have a checklist. Sorry.
1. You might start by getting the bank's last compliance exam to see if there are any immediate problems that have to be fixed or addressed.
2. Be ready to have forms changed if there is a name change.
3. If there is a regulator change, check lobby notices and be ready to change the place on the adverse action form where you put your regulator's name.

I have a checklist that I have used in a previous life. If you are interested, please email me at katoscano@flag.net