Definitely possible, but Dvorak is a near-term downgrade on Krej. Also we saw what kind of returns Phoenix gets on desperate GMs, so Boston can expect to pay through the nose for him.
Now if Boston can pull of Eichel, that's a different story. But I don't see Buffalo dealing him to a division rival.
Adams said he prefers the Western conference, but he also said he would be stupid not the listen to offers from any team. I don't know if Boston has what it takes to land Eichel in terms of assets. They want a 1st, 2nd, a top prospect and an NHL player, and dealing him to a division rival likely comes with an extra price as well.
Actually I'm not sure I wouldnt like to see them giving up everything for a guy with his personality, losing record and injury history.