What a beautiful brick - and lovely modern architecture. I'm a fan of modern, but if you want to make this look traditional like the cape cod then of course, that is an option. The shape of the brick fireplaces and window profiles are terrific - you must get awesome light from the clerestories.

Keeping the body mid-tone like the brick is a great modern choice as a baseline, but you have some terrific features to play up and highlight with accent colors. The range of colors in the tan brick offers a baseline and I would love to have a better color photo of the brick tones so I could play off them and suggest some things.

I would suggest a charcoal or warm charcoal roof color so you have more options on the body of the house - taking the roof gray or black allows you to have either warm or cool colors while the brown roof pretty much dictates warm - your home generally needs to be lighter than the roof. Since no one has shake anymore, it is okay to lose the brown if you can keep a warm gray shade. I love the Grand Canyon option to echo the original wood shake roof but both are attractive roofs.

You can definitely switch to a vertical board and batten / or reverse board and batten and be period appropriate but the challenge with that is that your brick has a strong horizontal line. Keeping the siding running in that direction brings more harmony.