Perhaps it's to be required to have Atlantians' blood, even if it's just a little, or to have some kind of underwater creature, like a kraken, among our ancestors for the cave to grant us these powers. I don't think you mentioned if the Atlantians could turn into humans when on land or not, if so, please forgive my forgetfulness. Anyway, if they could turn into humans and one of the caves lead to Germany, then there might as well be a possibility that one Atlantian traveled to the past, had a child or more who ended up being my ancestors. And the same thing could apply to my husband too.
Of course, everything I just said might as well be nonsense.