Distance of GK board from screed floor on the upper floor

That fits so far. Still missing as an example impact sound insulation and laminate.

With glued vinyl (3mm) and a slim skirting board of 4cm, the offered performance is a disaster. Unless tiles are installed, clip-on skirting boards for laminate/vinyl/design floor are unlikely to work.

And thus: the gap is MUCH too large for proper performance. Just ask him how he can still realize my proposed floor construction there. Or skip the skirting boards and say that you want to mount quarter round molding to the vinyl. And please post the answer. I want to see how the site manager starts sweating and loses his arguments.