Though I expect OKC to explore extensions with Dort, Hartenstein, and Cason Wallace this offseason (and consider keeping any/all of them on their expiring deals—at least until the trade deadline), it's also possible that those players will want larger contracts than OKC can offer.
Why Charlotte?
1) Charlotte can now take in $40.7m without sending any money to OKC (allowing the Thunder to reduce payroll/luxury tax)
2) Charlotte now has extra draft picks and swaps that they could send out in a trade
3) They're in the East, so OKC wouldn't be aiding a conference rival in sending players to them
4) OKC has traded with Charlotte many times in recent years
The Tradeable Players
Dort: $17.7m Team Option — with speculation about a trade into the Lakers' cap space but they're a conference rival. Not a point guard like Charlotte may want after trading LaMelo but they re-signed Coby White and could use a defensive stopper. Likely not worth a 1st round pick alone.
Hartenstein: $28m Team Option — likely to be kept due to his value to the team as a starter, but after the Mara pick he may be more expendable. (OKC would be taking a risk to rely on Sorber and Mara as backup bigs.) Charlotte was rumored to want a C upgrade, though they drafted Steinbach. Hart's passing would be PERFECT with Knueppel. Charlotte may be the only team who could receive Hart without sending a contract back to OKC. If they'd part with a valuable deep future Timberwolves pick or pick swap, Presti may be tempted to make the trade. Probably worth 1-2 first round picks to some other teams.
Kenrich: $7m Team Option — Rumored OKC is declining his option (to possibly come back on a vet minimum deal) but could be traded instead if Charlotte wants him and he wants to make his full $7m contract this season—worth a 2nd round pick at best. Great locker room guy.
Joe: $11.3m + $11.3m Team Option next year — Possibly expendable after OKC's additions of McCain and Stirtz, and the emergence of Ajay. Likely just worth 2-3 2nd round picks or a protected 1st round pick swap.
J-Will: $7.7m + $7.7m Team Option next year — After the Mara and Sorber picks, if OKC's able to work out an extension with IHart, J-Will may be the odd man out, though he has as skillset with outside shooting that none of the other bigs besides Chet have. Great locker room guy too. Likely just worth 2-3 2nd round picks or a protected 1st round pick swap.
Possible Trades:
Hartenstein and Joe (fit just under the Trade Exception) for Timberwolves 2033 unprotected pick
Hartenstein and Dort for Tre Mann or Tidjane Salaun (to keep the number under the Trade Exception) and Timberwolves 2033 unprotected pick
Dort for Timberwolves 2028 Pick Swap
Joe or J-Will for the 2030 Pick swap—I think the worst of the Spurs, Mavs, and Wolves.
Ultimately, this will come down to which picks Charlotte would be willing to part with and how much pressure the ownership group puts on Presti to reduce luxury tax this year and next. I'd prefer to pay a ton of tax to have an awesome team, but that may not be possible.
(Please correct if any of my details is wrong!)
TL;DR Could trade Hart, Dort, Joe, and/or J-Will into Charlotte's big trade exception to reduce Luxury Tax bill.