I would be surprised to see him picked off waivers. A 5'9/5'10 4th liner with 13 nhl games under his belt doesn't sound like he be picked as usually other teams also have players they are trying to get to the AHL without being picked.
Yeah, if we were already capped out, he would be in a good position to make the team with his low cap hit, added to the fact that he does seem to be genuinely ready to make the NHL.
But since we do have some cap space available and there are players we might look at signing to improve the team still... I don't think it's any great risk if Dumont goes through assignment waivers and spends another year in Hamilton (perhaps with recalls if /when injuries mount). The assignment waiver wire is not the time he'd get claimed, he's just too unproven to worry about that.
Though if we don't sign anybody else and/or he just comes to camp on a mission and forces management's hand, he's worth keeping around for sure.
Good news that he's signed now, either way.