36.5 cm aerated concrete and KS cladding? Ventilation behind or bonding?

We will only do the street side. I read something about "Hamburger Tradition" that you make a "decorative side." I liked the idea because of the boundary construction. Basically, I only want the bricks on this side. You are right that a 15 cm overhang (about 11 cm bricks, 4 cm air) might look strange. Are the glued slips just as "solid"?

It also says this above, and visually I don't find it bad.

No, they are cleaning substitute, much narrower, but made of similar material as real clinker. Visually indistinguishable afterwards.

Here it is also written above and visually I don't find it bad.

But it’s only 3 or 4 cm. Without the ETICS it would be almost 20 cm!!!

Are glued brick slips just as "solid"?

Solid yes. Just a "slice" of clinker. Just google clinker slips.

I'll start right away. Thanks for your contributions so far! I'll keep you updated here on what the plan is.