"Does one receive deductible credit from a "legacy" plan when one transitions to an ACA one or not?"
[ed: I had initially reached out to Anthem last Monday, but gave them a few days to respond before posting that]
I just emailed my contact to see if she'd gotten a definitive answer yet, and she's replied "I have not. Still waiting."
Since this seems to be dragging on, I've suggested to my client that we file a formal complaint with the Ohio Department of Insurance. I'll let you know if she's up for doing so.