I agree it is a big season for him. He had his bedding in season in 13/14 and last season he broke into the first team making a fair amount of starts so now he can hopefully kick on and show what he can do. All depends on how Brown plans on using him.
As for Jebb, I think this is exactly the type of player we should be signing. Someone who is young and probably rough around the edges, pick them up on a free and, I'd guess, fairly cheap wages and then turn them into a quality player in a few seasons.
Jack has yet to convince me he has got what it takes to make it. Agree it's a massive season for him. The midfield looks weaker with him in a 4-4-2 and in a 4-5-1, despite some great moments, he doesn't wow enough to jusify playing in the hole. League 1 should suit him more and I hope he does push on as there is obviously talent there.
Jebb is a no brainer as long as the medical is ok