I've been so caught up with the weird face and the fact I don't think he can see out of that mask that I hadn't even considered the thinner dreadlocks. At least for me, they don't matter nearly as much as a decent face. So if I was forced to choose one, I'd want a more P/P2 style face over thicker dreads.
As with any other variation in movie design (including face/mandibles) they can all basically be put down to difference in race, just like we have on Earth seeing as they've never been given any other context on screen at this point