I would use node given that your plan sounds like it will involve several distinct JS clients. I don't actually consider node/JS the most ideal choice for dev

I would use node given that your plan sounds like it will involve several distinct JS clients. I don't actually consider node/JS the most ideal choice for developing good backend habits if back end development was your central goal. But it will introduce you to a JS development process that is a lot better structured than you are likely to commit to when working with JS only on the client side. It will also make it easier to restructure with less of a mess if you realize you need to move between thin/online and fat/offline clients.