I just discovered that Luna has a pet in the comics · 4:30pm Jul 23rd, 2023
Apparently, in the MLP comics, Luna adopts a pet possum who she names Tiberius, with the adorable nickname "Tibbles."
You know what? I'm making this canon to the Shadows and Stars series. At some point in the Arc 4 timeline (so, after her return from the moon), she adopts Tiberius. Perhaps he could even make a cameo in a story somewhere... I'll have to think about it, but it's probably a yes, because look at this cute little creature.