Odds are Anya had a Nico Nico presence that's been scrubbed. Given she is likely half Japanese, she's probably been far more careful generally since she likely isn't a Muslim in an Islamic country.
I think Anya also filters out most of those that want to go digging. And, if she had some prep time, it's entirely possible everything was scrubbed. If you weren't overly exposed on the primary social media platforms of your natural languages, you can deeply scrub a lot of information.
It's entirely possible to have extremely little exposure in the States, so long as your name isn't known. Once that's known, it's all over.