The Hawks would do this trade as an attempt to go all-in around Trae and Johnson. They can take Zach into a TE and basically make two new TEs for Murray and Capela in addition to the two firsts and two high-seconds. That gives them a lot of firepower to try to get some help.
Milwaukee is rumored to be interested in Murray, and they simply don't have the picks to get a trade done. They have to trade ballast that can bring picks from a third team, and Middleton and Portis seem to be it. Of course, they could try to redirect Lillard, but that would be a tough pill for the team to swallow, and swapping out Dame for DeJounte doesn't actually get the Bucks closer to a le.
ATL25 would be the Hawks' price for letting the Spurs into the conversation. I don't see it as negotiable, so the next step would be to see how much value the Spurs could get for that pick. There are other second teams that could want Murray and/or Young and trade players the Spurs might want. This was my pick for ideal scenario because Middleton checks all the boxes and Portis is probably the second-best flex big in the league right now with Horford declining. I also think there is talent in the second half of the first that should be part of the discussion, especially if the Toronto pick doesn't convey. Considering the real chance ATL gets its together next year after a trade like this, I'm okay with giving up the pick here.
As mentioned, the Bucks are looking to retool around Giannis in the same way they were about him when they traded Holiday. They would struggle to come up with a credible offer for Murray without trading one or Lillard or Middleton, and I doubt their intention is to swap Dame out for a borderline All-Star after they gave up so much to get him. So I don't see any reason why Giannis would be on the table.
Anyway, I don't actually see Middleton's condition as a huge downer, seeing as the Spurs just drafted a high-upside SF in this scenario who would already be slated to take over from Khris anyway. That Holland would get some starts in during the season doesn't particularly bother me, and having a guy who knows how to be an elite perimeter defender there to teach a guy with all the physical tools to do the same seems like a huge bonus. This isn't supposed to be an off-season scenario that sees them become contenders. It's one more appropriate to where Wemby actually is and more of an evolution from where I think the team SHOULD have been this year had they brought in some lower-level vets and let them compete for minutes with the young guys. It's racheting up that compe ion while ultimately supporting the growth of the young guys.