Noctis Vs Luna
Luna has the same dress Stella had in the old trailers.
Luna is wearing a different dress.
Stella had stud earrings and a bead necklace in 2008
In 2009 during the meeting trailer she had no earrings or necklace
In 2013 she had star earrings and no necklace
Luna doesn't have any earings but has a moon necklace with a star inside it.
Either Stella uses Luna as an alias, Stella was renamed to Luna, the character of Stella was changed and a new character who resembles her was made in her place and named Luna, or Stella and Luna both exist as two different characters.
One pretty solid theory I heard is that Luna has a necklace of a moon over a star...what if she's an older sister who looks out for Stella?
What if something happens to Luna sometime into the game by the hands of Noctis, which triggers Stella to fight Noctis? That imagery could be symbolism for Luna looking over Stella like with that necklace.
Hey, but who knows, that stuff's back in 2008. We're 6 years removed from that. Speculation.
Yeh I thought of something similar to that, like the moon in the old 2008 trailer was foreshadowing something relating to a moon that will dictate what Stella does.
And that necklace having a moon surrounding the star could also reinforce that idea of a moon, Luna, looking over a star, Stella, could also be nothing though.
I've been thinking it may also have something to do with the logo, in the TGS trailer the moon Noctis is looking at fades into the logo with the face right in the center, could signify that the woman in the logo befalls some kind of sleep like state, possibly again foreshadowing Luna being central to why Noctis and Stella would fight.
Omnis Lacrima and Somnus both make reference to some kind of awakening too.
But speculation will only get us so far.