I suppose squad numbers mean absolutely nothing nowadays, I seen Ronaldinho wearing 45 for Athletico Maneiro the other day and seen a few players in Serie A over the last couple of season's have 70 and 90 etc. I personally would of given Colback 4, taken 10 off Wickham and give it to Sessegnon and taken 9 off Campbell for the arrival of Fletcher. Still a few more players will leave and there numbers will be taken by the 5 or 6 new arrivals when they get here
I don't really read too much into squad numbers as I think a lot of time players just have their preferences. Interesting though that MON has chosen not to allocate the number 1 jersey. I'm sure he's not thinking of bringing another goalkeeper in, but it sends a clear message that they are should both still fight for the position.