Alignment of location & shape of new building: square or rectangular?

Hello, we were able to secure a plot of land (with an existing house). We live and work in the immediate vicinity, so we are very happy that it worked out. However, it was quite surprising for us that it happened so quickly, so we are quite unprepared and are already stuck after the first preliminary discussions with four architects we approached. We have now applied for the demolition first (it can take up to 3 months for approval to come) and postponed the architect selection. The plot is difficult to build on, so we first told the architects only to put their vision of a house (for 3-4 apartments, maximum development) on paper. We don’t like any of it. However, we now know a little more about what we need/want... at least...
About the plot:
-13/1, 34/1, 33/1 is the original plot, we additionally acquired 31 (which is level and has a garden shed on it), the plot can basically only be used up to the red line, the height difference to the street edge is marked in red; steep slope, currently a steep stair connects the upper and lower part of the plot in the middle, the lower plot should be usable and accessible later.
-The plot should be fully developed, i.e. a small basement apartment in the underground garage (possible because of the steep slope) (4-5 parking spaces + common cellar) connected with the ground floor, 2 apartments on the 1st floor, penthouse, elevator, total about 500 sqm gross floor area.
I will live with 4 children on the ground floor + basement + garden (that will already be tight with a gross floor area between 160-180 sqm on ground floor + basement), 1st floor will be rented out and the penthouse will be occupied by my parents.
-Access to the underground garage and entrance must be from the east side so that south/west can be used as a garden;
-The house must be placed as far north (north/east) as possible towards the slope to create space for the garden in front and because that space is not usable otherwise.
-These are two points that were actually clear and logical to us from the beginning, but apparently not to the architects.

The basic question (all floor plans are rubbish, but we’re partly to blame for not giving people any guidelines; still, the question arises how you can plan only a 2-meter wardrobe space for 6 people...) is whether the house should be rather:
-narrow (about 11*16m): I find that visually nice, not so common here, pure west orientation, then a nice big living room to south/west or; a lot of space on the west side to design a practical stairway to the lower garden; problem: the two apartments on the 1st floor are one behind the other and the rear one would have a west/north orientation rather
-rectangular (e.g. 13*14): south/west orientation; 1st floor gets two apartments with south balcony, problem I have is that the living room then becomes too wide and has to be separated towards the east. Which room should go there? One design wanted to make the master bedroom with access from the living room. So that’s out of the question.

And what do you think?
Regards Benjamin

I would use the old building line on the mountain and leave the old wall as a retaining wall, slope protection (we did it that way) Lengthwise I find good, we wanted that too. Then it became square. Do you really want to have rental apartments in your house?

(Floor plans are all crap,

Especially invisible ;-)

-The existing house stands far too far forward (south) on the property. The space behind the house is wasted (especially since we bought the lower property) and there is a lack of space to the south;. We have good load-bearing soil, so it won’t be a big problem to move closer to the edge (not beyond it).
-Tenants: clearly not ideal, but we already live in a prime location here; that means expensive land... so you really have to get the maximum out of it. The whole thing will be expensive enough, so a bit of money should come back in. The apartments will go to my siblings, but they won’t move in themselves at first. And I prefer to rent two "small" apartments rather than one large one, it doesn’t matter if it’s only 1 or 2 tenants.
-I will show floor plans once we have agreed on a design/architect. They were all no good; this way it doesn’t work. Also, the architects had too little information from us.
- but I’m already looking forward to discussing them here.
Ben

Then there will also be good rents. No matter how stable the slope is (maybe not with rock), it must be supported and secured during the construction phase. Old wall removed and leaving the slope as is, even if it would hold, is not possible. That was one of the reasons why we did not go further into the slope. Supporting the slope, disposal of excavation, no guarantee that the steep slope will not slide later - possibly damage to the road running above, outdoor area with even more retaining walls. Our slope seems steeper than yours and it is very stable - not a sand dune.

Plan a larger five-figure buffer. I have seen it in our case, what still came afterwards. The structural engineer was involved from the very beginning - even before the demolition. Even then, something else came up (thicker ceiling, thicker wall on the slope side, much more reinforcement) suddenly the stone was so hard that the jackhammer was used. It rattles together.

I’m curious about the floor plans.