If the Queen "chestburster" is planned to be the same size in which it was originally shown, I could see NECA releasing the already-seen A3 creature pack contents as two separate sets - one with the Bambi-Burster, and the other with the Queen "chestburster".One is the Alien 3 creature pack for sure. We've all but seen it.
As for the second...
Though, depending on Randy's definition of "accessory pack", I could also see the egg set for ALIEN being the 2nd pack that Randy is referring to.
Of course I'd prefer that the unknown pack be something that hasn't been shown or hinted in any capacity yet. Either way, new ALIENS toys is good ALIENS toys!