Mix or imitate materials in the wall?

[Matkap]

Currently renovating a bedroom at home. We're going to switch to a smaller window which means we'll need to frame the wall a bit. The wall currently consists of wood paneling on the outside, insulation, a vapor barrier, and 13mm treetex on the inside. Should I replicate the wall's construction as much as possible? Should I try to find equivalent materials like treetex or masonite to use inside the room, or is it okay to mix materials? I'm considering covering the wall with the window with a layer of renovation plasterboard or regular plasterboard, is this wise?
I've also removed built-in wardrobes and need to frame a new interior wall here. The same question arises here, should I replicate the current walls or can I mix materials on this wall? Here I would prefer not to use plasterboard. On the other side of this wall is currently the bathroom, which will eventually be renovated and expanded in size due to the removed wardrobes in the bedroom. How should this wall be constructed?

Thanks in advance.

 

[Huzzbutt]

Not mixing materials makes future work easier, as you then know what all the walls consist of and the approach will be the same throughout the room.

 

[Tomture61]

Tretex has probably never been a good material!
Possibly sound dampening, otherwise flammable, soft on the surface, absorbs moisture.
Works well as a bulletin board!