Just picked up a new 2021 AT4 yesterday and wanted to say thanks for posting your sound set up. I was going to go crazy and do components, amps, etc. but decided I didn't want to do all that work and landed on just the speakers for now, pretty much following your lead. Went for the same dash and front speakers and then grabbed 6.5" rear Kenwood Excelon's that look the same as the 6x9's you got. For those interested on the rears:
Kenwood KFC-1666S
Item #1131666S
Have installed many a sound system in my younger days so planning to install myself. Lots of YouTube videos that show how to remove the door panels, dash speaker, etc. Watched a few to prepare.
Anyway, big thanks and will report back with my thoughts!