Whilst I realize that this is not a BOINCStats issue, I am wondering if it is possible of changing the name of an existing Team to a name that does not exists in BOINCStats and retain the credit of the old team. If it is possible, how is it done?

It would have to be done at each & every Project the Team is at now I would think. Change the Name at all of them and you should keep the Credits from the Former Team's Name ... I've done that in the past & it worked for me