Casting new edge beam for a new exterior wall outside the old exterior wall

[Gallahad]

I have a half-timbered house with paneling today. The paneling is in bad condition and needs to be removed. Underneath is a half-timbered house that is in terrible condition.
I've looked at Sto insulation system with insulation as plaster carrier and air gap, but it cost between 2-4 thousand per sqm.

My idea is to cast a new foundation outside the old one with L-elements and build a new wall in lightweight concrete, which is then plastered.

The exterior wall would then look as follows from the outside:
Plaster
Ytong 200mm
Air gap
Half-timbered construction
Air gap
Ytong 100mm inner wall
Plaster

Does anyone have tips on a similar project?

 

[Gallahad]

There are different opinions when I discuss with people.
One thinks:
100mm Ytong
Air gap
New wall of facade brick that replaces timber framing that is demolished, and built up to support the existing wall plate.

I am considering
Ytong 100mm
Air gap
Ytong 200 that replaces timber framing and supports the existing wall plate
Air gap
Facade brick

Opinions? Can facade brick function as a load-bearing structure? Feels a bit flimsy.