I really suggest that you defer pack purchase and focus on getting a pretty complete list of "all of the other stuff" --- either actually purchased, or at least stuff that you're pretty sure you'll end up with "that item or something similar in weight and bulk". Then you'll know enough to make a better pack choice.

As an aside, I suggest that for thru-hiking the AT you never need a bear canister, might do better to not think in terms of a "canister cook kit" (whatever that is sounds heavy and too much stuff to me), your ground cloth can be very light hardware store polycro ... I suggest that you pick out one of multiple excellent books on lightweight backpacking and read through that. Skurka's new book maybe, or Jardine, or Ryan Jordan's lightweight backpacking book, or Don Ladigan's "Lighten Up!", or Justin Lichter's new "Trail Tested" ... I've not read the latest of these, but suspect that any one of these will serve you well.