Dear alfredatai,
Thank you for your interest in the NXP MIMXRT product, I would like to provide service for you.
Yes, I also found that i.MX RT1040 not listed in AN12077.
I consulted with the relevant experts, response is that the RT1040 can refer to the RT1060.
I also check IMXRT1040RM, no PDRET domain definition in chapter 13.4.1.4.1.
https://www.nxp.com/webapp/Download?colCode=IMXRT1040RM
https://www.nxp.com/docs/en/application-note/AN12077.pdf
In AN12077,there are some description about Power domain bank assignment.

Wish it helps you.
If you still have question about it, please kindly let me know.
Best Regards
mayliu