My opinion is that the probability of life developing on another planet, advancing to interstellar travel, and being physically close enough to us to visit us during the last few million years is so implausibly tiny that anyone seriously asking about their relations with human beings can be safely dismissed as a complete rube.
It’s not hugely convenient without a VTT like Foundry, but properly codifying lying to the players is one of my favourite bits of PF2e. I encourage all my players to take Dubious Knowledge so I can lie to them even more.