At the bakery, there is bread, at the butcher, meat, and at the architect, house designs, so yes. You should choose one where "the chemistry is right," then they can not only design but also support you during the implementation.
In advance, the development plan is available and there are also some two-/three-family houses in the neighborhood.
I see nothing.
Can you just have something roughly designed here?
Yes, you can. With the architect, this is called a preliminary design. The HOAI has individual service phases for this (basic evaluation, for example). So you don't have to fully plan a house before realizing that you can't afford it or that it wouldn't be profitable as a rental property, or other reasons.