I'm going to build a house between residential buildings and want to do a central courtyard to provide ventilation and light in most rooms, will it be much more expensive than doing a front and back yard?
In fact, you'll need a project to determine the town planning conditions, plans, measurements, etc.. and know if you can do what you want, exterior yards cover the need to indent the façade in relation to the exterior alignment, usually at least 3m.... If it turns out that this indentation is necessary... it doesn't make sense to have an interior patio and build around it, unless the lot area is large and allows you to develop a house around a central patio, which, moreover, must be generous so that it is not shaded throughout the day.
Theoretically yes, but you have to hire an expert to confirm, it's a matter of design and measurements.
A particular solution may be the right one if it meets the standards of urban planning and habitability. I think they should be very similar economically if the surface area of the house and yard are the same.
Perhaps a house with a central courtyard has more corridor development and therefore more built-up area, and therefore more expensive. Also, with a central courtyard, it will be more difficult to provide natural light to the entire house, unless you are talking about a large lot.