I've been a regular AM user for 5 years and I just don't recall any Yuna. True, I have been out of the country for a few months here and there, but how did I miss all these reviews? They seem to run from 2009 to 2011. Yuna? Yuna? Nope, rings no bells at all.
I've never seen a girl by that name on the AM Tokyo page until a couple of weeks ago when this 'new' girl appeared.
Note the homepage: 'New Tokyo girl Yuna'. So, maybe she worked in Osaka, or Nagoya, and the reviews you've linked to are from punters in those areas. Anyone confirm or refute this?