A quick take on Wacha, FWIW. In watching him struggle in recent outings, I think his problem is mechanical. He appears to be physically fine, and can still dial it up to the mid-to-high 90s.
But something has happened to his mechanics. He tends to regularly release the ball too late in the delivery. I would think with some video analysis, looking at his work when successful and comparing that to recent outings, there are some adjustments he can make and get back to a consistently better performance.
Thus I would be hesitant to DFA him until I was sure his decline is due to something non-correctable.
Could Wacha be outrighted? If so, could some team just add him to their 40 man, or is there a way to retract it? If a roster move was needed, a DFA could happen since a trade could be worked out. Wacha, IMO, barring a miraculous turnaround, is likely gone after this year any way. But then again, there is Merandy Gonzalez, who could also be outrighted similarly to Meisinger, who no team claimed.
And if the FO wants to promote Edman, someone like Robinson or Urias could lost their roster spot.