I don't really know about other resources, but if you want to learn the technical nuts and bolts, Mastering Lightning is a pretty good book.

To answer your question, yes it is a hot wallet if you're running a node. As far as I'm aware, there's no real way to air gap your seed and the seeds work a little bit differently depending on the implementation of lightening you're using. You can't just pop in your seed and regain your channels for instance, you also need a channel state file to to restore channels.