Yes if it hadn't been that the FAQ only included the addition of fear then we would all assume that they followed both sets of daemon rules, that fact that they specify all daemons in codex daemons gain fear implies that they do not follow the daemon rule from the BAB and instead follow the rule as represented in the codex.
As the codex states that you get an invulnerable save equal to that on your stat line then the new models are a little stuffed
Who knows what save was intended for these models, Tzeentch models traditionally have a 4++ so it seems a little strange fluff wise to drop them down to a 5++ but I think thats the best they can hope for till GW clear it up for us.
You'd think that they would have someone with a good working knowledge of the game give stuff a quick read through before sending this kind of thing to the printers, they even got the Init value of the Alluress wrong in one stat block out of 6, its not rocket science