Even if possibly doesn’t read this anymore (which I would find a pity), maybe it will help others who are interested in the topic.
We built a wooden house in pretty much the exact style desired by the OP (just without divided-light windows). Concrete residential basement on a (slight) slope, plastered ground floor, upper floor clad with wood and large roof overhangs.
We are also in southern Bavaria and can see the Alps not only during föhn.
We built the house with Baufritz (basement by Glatthaar, since they coordinate closely with Baufritz). There is an installation level, and for the actual topic "mounting heavy things on the wall" we received the attached information sheet, which also shows the wall construction and possibly answers the OP’s questions – if he still reads them.
Besides the suitable anchors, there is of course the possibility to attach the heavy parts directly to the vertical wooden battens on which the drywall panels are screwed. Since there is a fixed grid dimension, these are easy to find – I always screwed the baseboard exactly here, so this is also easy afterwards.
Additionally, for washbasins, heavy lamps, etc., you can have additional wooden slats installed. This can also be arranged directly on site during construction. If you’re not completely clumsy, it doesn’t cost a cent more.
I also received all the manufacturing plans for the individual wall and ceiling parts, which show the position of each individual stud.
: check out Baufritz, their offers are very transparent and individual items are credited 100% if you do them yourself on site.
P.S.: Unfortunately, you can’t attach .pdf files here, so the individual pages are attached as .jpg.
