Yes, 3/2/1 waves are among the hardest loading schemes on the CNS. Doing 2 main movements with this scheme AND 2 assistance lifts that are compound movements is WAY too much for the nervous system.
I would honestly start with a lot less assistance work during both phases. Doing two main lifts hard PLUS two other big lifts for assistance with a lot of volume is too much for most.
I have created programs in the past with 4 compound movements in a session but when I did that the main lifts were periodized in a way that the sets for the main movements were not all-out efforts during most of the program.
The way I understand it every single one of the big lifts (4 exercises per session) will be trained all out on every set (3/2/1 waves are all-out and the fact that you are mentioning the double progression tells me that you will push as hard as possible on the ses of assistance work).
Unless you are a man with Godly recovery capacities I give you 2, maybe 3 weeks before you solidly crash.