Yep. It was mentioned in the Q&A section - someone asked if W-Y would be added as a fourth faction, and they said no - that W-Y would be lumped in with marines, but that they were looking at adding factions somewhere down the line by digging really deep into the IP, and that the first thing they were looking at was stickman (presumably since he's the only living alien outside of Xenos, Preds, and Predhounds we see in any of the films, as they don't have the Prometheus license).