If the Bucks get to the finals, I think you do all you can to run the same guys back next year. That means doing whatever you need to keep Middleton, matching a monster offer for Brogdon, and trying to keep Lopez, but otherwise finding another 7 footer that can stretch the court (they don't exactly grown on trees).
But what if the Bucks don't get by the Raptors? Do the Bucks try to do something to shake things up? The only fully controllable assets the Bucks have of their starting 5 are Giannis (who is not going anywhere for anyone), Bledsoe, and Brogdon (if they match an offer or extend him themselves). Is that enough to get another "star".
You're right. It's going to be complete chaos. Denver, Houston, and Portland are fairly stable as to who they are locked into, but everyone else in the final 8 could have massive turnover (Boston, Philly, Toronto, Milwaukee, Golden State) and that doesn't include the Lakers, Knicks, Hornets, and Pelicans (or the Rockets blowing it up and moving Paul or Capela).