Good observation on Seattle's success stopping the run against tight formations. This is the main reason that I see an opportunity for Tim Wright. We can run 2TE against Seattle and split both TEs out. If Seattle matches with a smaller defense to cover Wright, you run inside with Gronk blocking down from the slot or Lafell coming in motion. If Seattle matches up with a larger DT compliment or bringing Chancellor down into the box, it's time to throw the ball. If the matchup running against the lighter box is preferred, Amendola can be split out wide in lieu of having Tim Wright. (In fact, that might be an even better approach.)
I haven't noticed Sherman beign soft with the underneath stuff, but quickness is certainly a weapon with which to attack him. The underneath stuff against Sherman will work even better with him being banged-up and not as effective using his hands to throw off timing. Heck, split Gronk out wide right and see how Sherman likes handfighting a monster with a bum elbow. If they match-up with Chancellor, Sherman can try to cover Edelman in the slot on that side.