You can see that currently there is still a lot of wishful thinking involved and many things still have to be concretely planned / cut later with the architect.
With a budget of 450k, I am probably also well below your estimate of 600k.
At the moment, I take away that you prefer option B, even though higher development costs are to be expected here due to the greater distance to the road, but there is direct access to the garage in return.
When the time comes, I will clarify the site leveling and boundary construction with the building authority and my uncle.