This trade would take place in the offseason so all those guys heading to the Thunder wouldn't be under contract so you can just pretend they aren't in the trade. This is about trading up in the draft. I love Lue Dort he was actually mt favorite prospect coming out of his draft class because he reminded me of Russ, I was shocked when he went undrafted and super excited when the Thunder signed him and even more excited that he has found success in the NBA. All that said with the emergence of guys like Jdub, Aaron Wiggins, Isaiah Joe, Giddey, and SGA who keeps getting better this guard rotation is getting a little clogged. The reason I chose Dort to move on from is because I think the other guys will fit better long term or are just on better contracts. As a little extra bonus we're also freeing up a little cap space so that we could maybe sign a guy in the offseason.
Orlando has two top ten picks in this draft so using one of them to trade down and add an elite perimeter defender who can play any role you need him to seems like a good idea.
The Suns are in this trade because so the Thunder don't have to take on Garry Harris. For Phoenix they're getting a guy who finally found his jump shot (he's shooting 44% from three on good volume) and they're getting him for pretty much free.