Actually, I don't think Draco is James either--there are difference between the two of them as well. But I do think that there are parallels between the two of them, including the ones that you bring up here. Particularly the outsider status of Harry and Snape, the perceived arrogance/confidence of Draco/James. Even if Snape/Draco are the DEs and Harry/James are the Gryffindors and ultimate golden boys. That's what I find so interesting about the Snape/Draco relationship, actually. They're such an odd pair in so many ways!