One of my design concerns is stairs location, I think that it should have main entrace character. That's why I anticipate a bit to make the following proposal.
I'm moving the north garage more to the north, to relocate the stair in the center of the building, with this design the home appears larger, but the square footage of construction will be the same.
Stair design should be a fundamental element in the set.
answering your question about the spaces, I can comment that all spaces are comfortable, the only place that I feel a bit tight is the den/media for their double feature, you must also consider the size of the screen and how many people want to be there at the same time, but I tell you beforehand if you are fan films, or if you want your small library (because I have understood that you enjoy reading) this space is not enough. among other things, I take the liberty of extending the den/media, this expansion gives a nicecantilever effect.
below i add some renders as first drafts, I am open to criticism.
Front yard design isn't final yet, but I suggest something very simple without much foliage and then propose a heavy landscaping design on backyard.
I believe that north garage is that you'll use most regularly. why I put a door that connected directly to the stair so you don't need to go around.
Terrace garden, is one of the most representative elements of modern architecture, since Le Corbusier.