"...and you still had to meet the hiring requirements for Delta to qualify for the interview, so not a true flow..."
Zonda,
I used to have the details of the E-to-D from the website but changed computers recently. I didn't bother saving a lot of stuff but what I remember is the Endeavor interview was the only one involved. DL personnel were part of the Endeavor interview process and had a major say in hiring the applicant. After meeting some criteria like a certain amount of capt time at Endeavor and slots open at DL, you just flowed up to mainline. That's what caused the big stink. And, you couldn't apply to DL outside the E-to-D pipeline if you were in that pipeline.
I recall a very small number of applicants were hired via that plan and I lost track of the existence of the plan itself. And...my recollection is always subject to revision. ;-)