If Esta had heard all this, one hour earlier, it would have occurred to him to wonder if 'Merrin' is perhaps, somehow, a completely alternate version of Mariona from some kind of shadow of Golarion, if Mariona was outright replaced and not just inverted. For much of this does not sound like a direct mirroring or inversion in particular, and parts of it do not obviously match up with his remembered Mariona at all.
Thankfully, Esta has by now seen the key piece of evidence which contradicts this.
Because if Merrin was really from some entirely different world, related to Mariona only by some strange coincidence of appearance, or magical shadowing effect --
-- then why would that country -- or perhaps entire planet, for there is no mention of distinct countries, in her words, or even distinct cultures --
-- why would that whole country have a rule specifically saying not to tease Merrin about her future potential if she ever acquired ambition, as Esta specifically teased Mariona about, and Mariona specifically hated?