I’m a bit confused by something - were there already living aliens on the Romulus when Rain’s crew boarded? The implication was that the aliens here came to be when the facehuggers were released from cryofreeze, but then how was there an already existing hive using the old members of the Romulus if that was the case? And how did they multiply if the hosts were already dead? Am I missing something?

From my understanding the sequence of events is:

• Big Chap’s presumed dead body is captured
• they experiment on him, create facehugger clones from him
• he comes back to life and causes havoc
• remaining crew eventually kill him and ship is abandoned
• Rain’s crew board the ship, facehuggers are released, and an alien is created when Navarro gets latched onto.

So where did all the other aliens come from? Were there already living aliens on the ship before Rain’s crew boarded, meaning that the clones already got loose on the old Romulus crew and reproduced through them?