Rewards are once per week, per class. You may have found a loophole last time by picking up the bounties on all your hunters before turning any in, but this time, by turning them in on one hunter, it counts them as complete for all your hunters, as is intended. There is no benefit to having more than one character of the same class. You would be better off deleting two, and making a warlocl and titan, and playing them as well, as you would then have three time a as many powerful/pinnacle rewards each week.