Back to topic:
Maybe ( but only maybe) we see whole thing joined to " Predaliens regurgitating reproduction method" a little bit wrong.
If brothers/Fox wanted creature to use new method of reproduceing, why they added facehuggers to this film? I`ve come up to idea that regurgitating can be used more litteraly:
- We don`t know how many huggers in on board of Pred ship.
- We do know that both huggers and PQ will survive crashland near Guannison.
- We have seen a group of chestbursters in kind of nest.
So maybe PQ is not just impragnation people via her mouth but rather kill and eat people. Then go back to the nest were chestbursters are (from normal huggers), and regurgitate flesh for them. Chestbursters need to eat in order to grow to adult form ( I know it is not canon but we`ve seen it in AvP2 game). Maybe whole process is used to make them grow faster and earlier become the guardians for Queen, who can now safetly start to grow her egg sack.
Support to this opinion is fact that we do not have any other predalien. If she can reproduce via mouth to mouth, she could easily implanted injured preds on board of scaut ship.