They were talking about enemy types, not outfits. As all of the specialist outfits are already available in the base game.
Adding the Morningstar specialist should, in theory, be pretty easy. Just adding adding a line to notoriety_spawn.xtbl to tell the game to spawn an oppressor with two goons with snipers on each side, should do the trick. For the Decker specialist, I don't think it's even possible, unless all of the animations, effects, weapon model, etc are still in SR4 as legacy content from SR3.