I think you could make it work.

After all, the Shakers invented the Round Barn!

They had curves and arches. Don't worry.

There are obviously houses where cherry and soapstone wouldn't be the best choice -- a swingin' 70's ranch, for example. (Having said that, someone will find a fantastic pic of a 1970s house with insane cherry and soapstone, and I'll have to eat my hat.)

But yours seems neutral enough, and your chairs and stools are simple. Even the arch is a simple arch.

The key is (duh -- Shaker!) simplicity. You don't want to drown the Shaker theme by adding Shaker elements.

Just think of it as a neutral, like black trousers, and do your thing, just as you planned, with as many of your other choices as seem appropriate.

I hope you get your first choice though!

I think it'll be fine, especially if you're careful about the finish. Your house is pretty much now, and so is the style kitchen you've pictured, and the wide arch. The word "transitional" is overworked, but generally fits anything that has past elements in today's design framework, and that's really what you have pictured. The word "Shaker" applies to the simple recessed panel, not the minimalist design philosophy here.

The woods in your picture of the stairs are honey colored (medium golden brown) and in your kitchen drawing they're more spice (medium-dark orange brown). Since you're opening up your house rather than separating off the kitchen, I'd be more concerned with making the woods work together than the cabinet style (which by being so simple should go with anything).

Just make sure you're happy with the choice you make! There's no point starting otherwise.