If ever there was a time to throw Brady back into the mix, it is now. With Gronk hurting, Hernandez potentially facing jail time (police are at his home as I type this) and a serious lack of depth at WR right now, Brady could be close to average this season. His numbers last year when Gronk was off the field were pretty pedestrian. Beyond that, QB is so deep this year. You should be able to easily pick up one of those guys you mentioned. I'd target Wilson, Ryan or Dalton myself as I see them having value and upside in your keeper format.
If you can keep Guys based on their round, this is a no brainer since Graham as a 7th saves you about 5 rounds of value and Morris as a 9th saves 8 rounds since he is undoubtedly a first round pick this year. A lineup built around the #1RB, #1TE and another top 10 RB would be a pretty outstanding foundation.
After giving it some thought, if you can't keep both based on position I'd keep Graham and Charles and throw back Morris but I don't think you can go wrong with any combination of Morris/Charles/Graham as your two to go along with AP.