I would have been fine with this return for Jax, but wanted another prospect (Seth Johnson would have been nice) in return for Duran. "Proven closer" still carries some extra weight.
I will point out that Duran wasn't nearly as highly regarded as Abel when the Twins acquired him for Escobar. If it turns out well, the Twins just got Jeffers and Ober (or Jeffers and Jax) in return for Duran, however, as has been pointed out elsewhere, the Twins took on more risk in the deal.
The really sad part to me is the Twins missed their opportunity to get Duran to sign a deal that locked him up with the Twins until he was 30. They're going to miss out on Jeffers as well. Those are huge failures by the current front office. The Twins have to extend their talent below cost when they have the opportunity.
I hope this means they are going to be able to dump Correa's salary on Houston. There is no reason at all to pay him $32M a season to play for a rebuilding team. Sell Coulombe, Bader, Castro, Jax and Stewart as well.