Yeah I also wouldn't be surprised if they bypass the singles and go straight to trades with some of these, given that they've got less than half a year to get this last stuff out, which is ok by me since I was planning on trade waiting anyway.
I'm definitely concerned about the disappearance of Predator: The Original Screenplay from sites though. Given that we saw preview pages of Alien and the first couple of issues of that are still up on Dark Horse's website I'd assume it must have been further along than this was, but man I'm going to be disappointed if it's been canned. Those would have been a great couple of complimentary titles to end Dark Horse's run as a whole on, and it's not going to be quite the same now if we only get the one.