5 years ago
Your best bet is to just read whichever series' omnibus you have in the order they were released. The Aliens stories are pretty much in order, and the AVP stories are reasonably easy to follow. The Predator stories tend to spread out through history, so you don't need to worry about read them in any particular order past the first three storyline (Concrete Jungle, Cold War, and Dark River) which are in order anyway.
The early AVP stories (centering around Ryushi and Machiko) make up a neat little micro-continuity that fits together, but again, they're pretty much in order anyway.
There's one weird bit where characters from an Aliens story (Berserker) show up in the second AVP story (Prey, I think?), but you don't need to read one to understand the other, and frankly, Prey sucked anyway. So the short answer is no, you don't have to read the volumes in any particular order.