No. 2: The Miami Heat make sense
The Miami Heat are mentioned in trade discussions for most any star player, and with good reason. Their market makes it reasonable to re-sign stars, they have an elite organization and a track record of finding role players on the margins such that they can afford to move prospects and picks to land stars.
Even more so, their current roster construction has a Donovan-Mitchell-sized hole in it. He would be the perfect on-ball creator to pair with Jimmy Butler and Bam Adebayo. The Heat have a collection of picks and matching salaries to make this conceivable. It's possible that the Cavs won't value Tyler Herro highly enough for the Heat to win negotiations, and the two teams would absolutely fight over Jaime Jaquez Jr., but it's realistic for the Heat to be in the discussion.
No. 2: The Oklahoma City Thunder don't make sense
The Oklahoma City Thunder are ahead of schedule, growing up before our eyes into a legitimate title contender. Shai Gilgeous-Alexander is an MVP candidate, Chet Holmgren looks like a future All-NBA fixture, and Jalen Williams is an excellent wingman to SGA. Yet given the Thunder's deep collection of draft picks, it's natural to think of them as a candidate to cash in their chips for another star to add to the mix.
The Thunder seem like a team planning to be patient, but even if they were ready to push the chips in, it's unlikely they do so for a player like Mitchell. They have their No. 1 option and an elite backcourt player in Gilgeous-Alexander, and their approach to team-building is to go after length and skill; it's highly unlikely that they would pair SGA and Mitchell.
What's more, as competitive as the Thunder are right now and moving forward, Oklahoma City is not a place that most stars want to live. The Thunder would not only need a small backcourt to work but they would have a ticking clock to convince Mitchell to stick around. The situation and the player don't make a lot of sense for the Thunder. If they make a move, expect them to target a forward under contract.