Hi @Yevgeny_Libov ,
You wrote "This step adds both device templates under the same template stack." This is incorrect. The step actually adds both devices to different template stacks. Once you are done with the steps in the document, you can actually delete the device group, template, and template stack created by importing the 2nd NGFW (step 7 #2 and #5). At the end of the document, you should have both NGFWs in 1 template stack with 1 template. You do not need separate templates for each NGFW in an HA pair. Unique settings such as management IP or HA link IPs should be (1) managed locally (no config in Panorama), (2) overridden locally, or (3) use template variables. Everything else should be the same.
Correct. The device is associated with the template stack, and not the template.