Why for each:

Cavs: Murray and Mitchell would be a good backcourt pairing. Hunter adds some size on the wing whether he starts or not. Champagnie was thrown in to make the money work. Spurs could send a different small salary if they want. As part of eating Hunter's deal, ATL sends the protected Kings pick. Spurs 2nd wasn't available for selection, but that would be #35.

Hawks: They've been looking to dump some money. This trade let's them move Hunter's contact, get their picks back, get immediate cap relief, and free up a ton of money next summer. They still have their lotto pick this year and some other pieces to make additional moves. I don't necessarily think they'll tank, but since they get their picks back here, they won't be as pressed to make unnecessary moves to compete. It also opens up the possibility of moving Young.

Spurs: They add Garland for pretty cheap all things considered. While they won't have a ton of money to play with in FA, they still have a bunch of picks to trade and the keep Keldon as a chip they can use.