Pistons
Jrue Holiday feels like the perfect Pistons player. Elite defensively, great shooter, secondary ball handler next to Cade, and a culture setter for a young team that needs an experienced vet who has done the exact thing they are wanting.
Though the trade machine doesn't like this, if the Pistons renounce their free agents, this does work. They would also have the Full MLE and might be able to re-sign 2 of Schroeder, THJ, and Beasley.
Celtics
Celtics get under the 2nd apron and they get a 2029 first rounder to replace the one they traded for Jrue. Fontecchio could be a back-up wing if Hauser is traded, but Fontecchio also is an expiring contract that could give C's some flexibility the following year if they go the free agency route, (though trading Brown would likely be necessary for this).