Soooo
1) I just got my physical Legion Collector's Edition and upgraded my account. It was already digitally upgraded to Legion.
2) I contacted customer service to give my digital Legion upgrade to my wife. (If anyone else is doing something similar, you'll need your friend's email address.) It went through, she got Legion applied to her account, as well as the character boost.
3) My account kept the character boost from the digital upgrade, and now has AN ADDITIONAL boost from the physical upgrade.
TL;DR I got a second character boost for free.
Yeah, I just upgraded my account and also noticed the second boost available. I've put in the ticket to CS to refund my standard key (last time they mailed it to me and I was able to sell/give it away myself without needing a friend's email address), but until I hear from CS, I went ahead and used both boosts on the off-chance they wouldn't retroactively remove one of them.
With WoD, this didn't happen. Maybe this is their olive branch to CE buyers who are stiffed by only getting a key back instead of $$/game time?
Hopefully it sticks for us both!
I have a 100 hunter and DK to add to the stable of alts now!
Btw, how did you contact CS, through the ticket system as well?