There are still several “drop location is unknown” vanity pets to be added ingame.
Personally think the Wind Rider and Gryphon will be faction specific, perhaps bought directly from the mount vendor near Krasus Landing? I have been told that the Pandaren Monk is BoA, so that isn’t included in this, however, one of them could be for another pet achievement, probably 100 pets. Personally hope that they include a 100 pet achievement with the Icecrown patch, or with Cataclysm, and the Core Hound is the reward, in my opinion that would be a decent outcome. The Zipao Tiger uses the same model as the cat in the Oracles quest, so perhaps related to Scholazar Basin/the Oracles in some way. This is all speculation on my part, but I think it would make sense. Lil KT and the Pandaren Monk are, however, a complete mystery to me..