Like I pointed out earlier, look at the new quotes. There's no way this is going to be set between movies. Debating how is pointless.
He says that he thinks the third movie "never happened" and that, speaking of the post-'Aliens' continuity, "that's not the world I want."
Like it or not, this is going to be its own thing. It's replacing those movies - which is a better idea. Otherwise, there's no suspense and we'd already know what happens to Ripley and co.