In 6 of the past 7 seasons, 6 WRs were on the 53 to start the season. One of those will be Slater.
Of the remaining 5, I'd say Jules and Amendola are locks to start on the 53. Lafell's status is up in the air. He's deserving of a spot, but keep hearing PUP. If he's on the PUP, that gives us potentially 3 WR spots.
Wayne and Dobson could be two of those, but that leaves a potential 3rd WR. Could be Harper, could be Thompkins. Or maybe BB decides 5 is enough. Or maybe it won't be KT because of special team considerations.
But there's definitely room on the opening day 53 for a potential 5th WR, even without exceptions for injury prone (Dobson) or learning the system (Wayne).