Nothing says it can't be done, most just don't do it.
You can surely put the Blitz on top of Z-2, but this would cause you not to be able to layer on the Z-2 on top of the Blitz. The will not bond because of the oils and carnauba in Blitz. You would have to dawn wash the car to strip the Blitz and Z1, Z2...etc etc.
The Zaino is supposed to be used in a system, of Z1, Z2, Z2, Z2...etc. and Z1 again every 5-10 coats of Z-2.
I still remember when I was a die hard Meguiars #7 polish/3M Imperial Hand Glaze user with a follow up of two light coats of Meguiars #26/Blitz depending on the paint I was working with and the mood I was in. This was before Klasse, Zaino, and the new Blackfire was introduced into my vocabulary. Was it Beau, Moe, Huy, Richard, Don, David, or Brad who introduced the Autopians the Klasse?
Whoever it was thanks!
Jason