In a ideal world Luna would be an energetic and spunky three year old running around, curious about her younger brother, happy whenever he learns something new, and excited for the day when he starts talking and she has a peer to talk to.
And Robyn would despise both of them for not being perfect breastfeeders and having independent thoughts and desires. Although to be fair, if Luna was a functioning child she very probably wouldn't have had Atlas in the first place. Seeing as how she used to discuss how she's destined to have three kids, but since popping out an actually normal baby she hasn't talked about that in a long time.