I would expect Milwaukee to pay the luxury tax if that's what it takes to keep Giannis content, not that I have any clue about their relationship. But personal relationships aside, I'd guess they'd be more likely to part ways with Bledsoe because of his age and injury history plus the likely contract demands they'll see from Rich Paul.
I wouldn't be surprised to see Dinwiddie traded but I don't see why they'd really want Ariza or especially KCP.
As far as New Jersey, the reason they would do it is to get some kind of a young asset or draft pick, so I tend to agree a first rounder would have to be sent as part of the deal - hopefully just the Milwaukee one.
I would keep Brogdan over Bledsoe any day of the week. With that said they had Brogdan when they traded for Bledsoe, and Bledsoe is the starter now.
I think they do value Bledsoe more highly, and they are trying to compete now. I am just guessing but I think they might rather have a more traditional shooting guard, another wing, or an upgrade at center rather than having two pg's sharing minutes on big contracts.
I don't know that Brogdan is really available - just saying if I was the Suns I would definitely be inquiring.