Hmm... Maybe we should ask you to write some sleepers for us...
All three of the 2-start pitchers you're considering are good options, although they're obviously not can't-miss picks. Of those three, I like Lackey the most for next week, but it's very close.
The trouble is, your regular staff is excellent, so you may not want to tamper with it. In the end, it comes down to your needs: if you're in a tight whip or era race, stay put; if every win helps, drop Moss (again, which pitcher to drop is a very tough decision), and pick up Lackey.