I sent FW an email to confirm, because it is a little grey. At the beginning of the Doom of Mymeara book it talks about the different stamps of approval. Anywhere there is a single unit listed it gets one of those stamps. The army list as a whole does not have any stamp on it. However, the language FW has been using lately seems to indicate that everything intended for 40K play (not Apoc) should be allowed in 40K games.
In the most recent FAQ that FW has released concerning Psychers they update a few of the Badab characters, as well as units form the Doom of Mymeara book, to fit with 6th. They also Errata the Tyrants Legion and Corsair armies with a list of who they can ally with.
I will wait for confirmation from FW in their email but it seems to me that Badab Characters, Esyllian Drop Troops, Tyrants Legion, Death Korps, Corsairs exc. are all intended to be, and should be, aloud.
All FW stuff is official now. You no longer need you "opponent's permission" to use FW units. No where in the Doom of Mymeara Book does use the language of the old FW books (akin to special characters in 3rd edition) that you can only use these models with your opponent's permission.
However it does say that because FW units are less common you should be upfront with your opponent and show and explain what the units are and do.