Personally I think Batherson is a cut above the other guys.
I adore Brown, think he will be a very good player, maybe the best of the group, but dont think its gonna happen in Ottawa.
I like Norris a lot but see him more as a 2nd liner who is good at everything, great at nothing, but can score on the PP. He is probably more of a 3C right now, if not a 4C, but gets a lot of chances and has decent finish. I think he'll be a pretty consistent 20-25 goal, 45-55pt guy who is really good on faceoffs and 50/50 pucks and plays responsibly.
Brannstrom I see as a 3/4D who can provide a unique element from the back-end. I think he'll be a good player.
Not sure I'd do Batherson for Fabbro but I would, without a doubt, add a decent piece to any of the other 3.