The more I think about that quote the more I think Trigger was referring to licensing and not necessarily "continuities", which is something we knew Fox did anyway. Like, we knew Gearbox has licensed 'Aliens: Colonial Marines' as an 'Aliens' game only, so they actually couldn't include Predators in it, whereas 'Predator: Concrete Jungle' got licensed as both a 'Predator' and an 'AvP' game, which is why it has a whole bunch of nods to the Alien and AvP franchise as well. A lot of the comics and whatnot are somewhat similar, where some "AvP" specific stories will include references to things that happened in specifically "Aliens" or "Predator" comics.
Trigger's comment doesn't really make sense in terms of "continuities", because it's clear that the AvP stuff is meant to occupy the same continuities as the A and P stuff, what with pulse rifles, "Weyland-Yutani", etc, not to mention the titular creatures. So for storytelling purposes they're meant to occupy the same "continuity, but in terms of licensing, that's a practice we knew Fox has been doing for a while.
It's similar with the Terminator franchise, where a whole bunch of different companies actually own the rights to different aspects of the Terminator franchise. There are 'Terminator Salvation' comics that are licensed from a different company than the one that owns the rights to 'The Terminator', but the storytelling implication is that they all take place in the same "continuity", even if legally the 'The Terminator' comics can't make reference to "T-1000s" or "hydrobots" and whatnot.