I agree with your choice to keep Charles and Forte. Two strong RBs to start the team is a great start to any keeper team. With that in mind, Bryant or Jackson is a bit of a toss up player wise. I think in the short term, Jackson is a better play. He'll continue to put up explosive points, with some down games. In the long run, Bryant will probably put up better points. Depends if you're looking towards the future or this year. Overall, I'd probably go Bryant. You're getting a comparable receiver, maybe a bit more consistent, for a better price. Take the value pick, hope he stays healthy, doesn't go TOO prima dona, and continues where he left off before the injury.
Good luck out there.