The first thing that led me to this is that they both share the same last name of "Mhakracca". However, that's not enough information since it's a common Keeper of the Moon last name. Fortunately, since my server unlocked the "tell me more about your family" selection in Masha's dialogue, I was able to dig deeper.
So basically, shes the third child of five who came from The Black Shroud. She also mentions she has an older sister who moved to Ul'dah and then mentions this:
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FESS UP SE