Yoan Moncada was the consensus #1 prospect in baseball at the time and Kopech was consensus top 30. Compare the value of the top 2 - Kopech and Vaughn are what, 1 top 15, one top 30 right now if they counted? Kopech might even be top 50? If Vaughn is the centerpiece, he's way below the value of Moncada at the time, generally he's somewhere around #10-15 so something else has to make up the difference between a #1 prospect included and a #10-15 prospect, and that has to be pieces 3-4. That's how I got to Vaughn, Kopech, Cease, and Madrigal - top 2 don't match the Sale deal, but back 2 make up the difference.
Madrigal (top 100), Dunning might be borderline top 100 based on what he did this year, Cease and Stiever are outside the top 100 but moderately close? Even if Tampa Bay really, really liked those guys, they can easily find better talent.