I think the there's a big chance that it would be set during the later years of the Engwythian empire;
and the story would explore premises and immediate consequences of gods creation.
This wouldn't really make sense given the trailer; the flags show Woedica's broken crown which would have become her symbol some time after the gods' creation.
The Aedyr empire is something like a thousand years old, so this could plausibly be set 100+ years prior to the Pillars games
It's just a speculation on my side, but I don't think the gods were created just randomly.
More likely than not, their creation was affected (if not outright prepared even) by cults or organizations with certain sets of beliefs.
Also, considering impact the mass sacrifces causes, it would not be a stretch of logic to expect Engwithian to prepare for the future by setting up Leaden Key and maybe it's connection to Woedica beforehand.
Maybe through the eyes of a Leaden Key agent, perhaps even Thaos himself.
Last thing I'd expect from this game is a pre-defined MC, worse yet a pre-defined MC that's already been used in the story.
Tho imagine Obsidian pulling a Revan, that halfway through our custom character turns out to be reincarnated Thaos
Yeah, that's the whole thing with animancy and the wheel of souls, - the body is just a vessel for reincarnating soul.
So "Thaos" can really be male or female of any race.