Ok, here's my Take on the ALien life cycle problem thingy:
The Queen, when in danger and knowing that it will definatly die, can basicly spit a super face hugger (no egg) out of it's tail which is what the Queen in ALiens did just as it was suck out of the ship and the superfacehugger was able to grab onto the outside of the ship. It than crawled around and found and burned a hole into the ship, which cause a fire and made the suluco (or however you spell it) launch the escape pod thingy. The super facehugger than jumped onto riply and than, obviously, the dog.
In AVP, either Scar kill the facehugger just before it reaches him, or he wakes up and cuts the chesburster out (and than heals himself). Either way, the chestburster does not come from that facehugger. Then, at the end, when the Queen stabs him, as it feels the sudden pull of it's chain, it spits a super facehugger out of it's tail (which of course stays inside of Scar's body. The facehugger hides in there until safely on the ship, where it spit's the embryo directly into Scar's stomach (in my version of the story, Predators can be facehugged when dead.) Than, like at the end of AVP, the chestburster (before properly made) pops out of the stomach, before making a hole in the chest, and going in there as it is supposed to. Then, as shown in AVPR, it bursts out of Scar's chest.