I'm kind of whatever on Hicketts. Rooting for him for sure, since guys his size making it in the NHL are kind of underdog stories, but I don't see him being more than a third pairing PP guy.
I'd love to see Hronek make it after his really good rookie year and the fact that he's my #2 prospect in the system right now. But if the power play is gonna feature the likes of Green, Kronwall, and maybe Hicketts, then Hronek should go back to the A and work on being the top offensive blueliner there.
Cholowski needs to get some pro experience and I don't expect him on the team unless he really crushes it in training camp. Fortunately he's bulked up since draft day and is 6'1, 195 according to reports from development camp. I think he might actually have a higher ceiling than Hronek, but he needs to prove himself in a pro league first.
Sulak is a wild card given his age and lack of NA experience. Maybe he'd be an okay option as a 7th D, since he's done growing and isn't likely to develop too much more, so not playing everyday would't stunt his development too much. I fully expect him to start the year in GR though.
All in all I expect it to come down to Hronek v. Hicketts in training camp with the loser of that battle being the first injury call up. Sulak probably gets a look later in the year and depending on how he does maybe they look to give Jensen the XO treatment.