Our Operations Dept would like to send an email offering Christmas Club account holders the option of an AFT into another one of their accounts with us in lieu of issuing a check.

Do the requirements of 1005.10(b) Written Authorization apply if the AFT request is for one-time only?

For ongoing AFTs...do you allow a customer to verbally agree and document that agreement onto a AFT form?

We are planning on sending a letter to Christmas Club members stating that we will deposit their money into the funding account instead of receiving a check. Is there any issue to this?

One or more of your customers might not like it. I haven't used a club account for decades, but if had one and had a reason I wanted a check at maturity rather than backwashing the funds to my funding account, I might not be happy. If you offer it as an option rather than present it as a fait accompli and then only accept club accounts with that feature next year, things might go more smoothly.