For those of you who have a Draenei character now high enough to do the Onyxia attunement quests in BRD, you can now complete them, the note will drop. Before no matter how many you killed in BRD the note wouldnt drop for Draenei characters but thats been resolved and I confirmed this through someone else though I have not yet tried myself at this moment.
I stil am not Onyxia attuned and have been carrying Marshal Windsor's note on me for a long time...so if you are on at my weird time slot- I'd love to help any Draenei alts out there.
Hmm i havnt even started on Onyxia attunement.....