My guess is that Node is responsible for serving the HTML/CSS/JS that's used by the front-end, and probably providing an isomorphic Ember endpoint down the road. So probably in the realm of knowledge that a front-end dev would need, but not a front-end tool in that it doesn't run in the browser.
Yeah, we're definitely interested in seeing what's possible with isomorphic Ember or React code. We don't necessarily require Javascript developers to come in with Node.js knowledge, but they should be interested in learning and a desire to holistically understand the web stack they're building on.
