I too got a notification in HotS that I got the portrait/mount in HotS, pet in WoW and cardback in HS. Didn't get the pet in wow yet either.
Edit: While relogging between toons not half an hour after posting this, little Graves was waiting in my bags on a rarely played alt and I had gotten the FoS without pop up notification. Was by pure luck I saw him in my bags, so be sure to check.
Edit2: Same toon ALSO got Graves in a mail from Breanni. Good Guy Breanni making sure you get your pets!