One of my friends came up with the ship name while I was getting attached to the ship ! It was really cute. (Shout out to Sousuke who's not on Twitter but has been my personal friend for soon to almost be a decade)

Sona has a motif of astronomy/astrology. It's his hyperfixation so thus, lunar.

Then for Itsuki, he's a hacker/has a computer motif so thus, matrix. Funny enough I've never watched the matrix though nor do I usually the word casually in my writing.

I will call them LM for short a lot if I don't feel like typing the full thing.