Omg so easy. I always have plot bunnies but have no talent for writing so I just research it instead and just day dream stories when I'm bored. So having the same issue I consulted the baby name generators (insert parent name, origin -optional- and gender) and bam I have names! I like all three separately and equally but you can choose which is your head canon:

Alexis Barton
Meaning : Defender of men (from Alexander)

Sasha Barton
Meaning : russian Pet form of ALEXANDER

Anya Barton
Meaning : Gracious, merciful

Or my favorite combo: Anya Alexis Barton (Gracious/Merciful defender of men) and Sasha is Natasha's nickname for her (since she's Russian; or at least she was)

I don't know what it says about me that I have thought so much about the name of the fictional child of two fictional characters' fictional relationship when I'm not actually writing a story, but good thing I have so I was ready for this :)

In advance thank you for feeding my kid!fic addiction!