Why does everyone think Luna is Stella?

[Fynn]

Probably because of the fact that she looks extremely similar to Stella and we haven't seen or heard of Stella since the game got rebranded, unless you count that one image of all the faces from the end of the E3 2013 trailer.

Although I suppose the little girl in the beginning of that same trailer who's shown running with Noctis and the voice we hear telling him to live his own life etc. could be Stella. Or Luna. Who knows.

And there names are...?

Nobodies questioning the existence of the character we knew as Stella, just her name

Like I said, we haven't seen any of the evil old folks since E32013 either, and yet no ones questioning their existence.

Sorry - I'm really sleep-deprived lately

Anyway, I think my point stands, I doubt they would change the name so unceremoniously. I'm still pretty convinced they're different people. Mostly because he similarity between the two doesn't seem like a simple redesign for me. Her eyes are slightly smaller, the jawline is different and the nose is really unmistakably something else. I think they're siblings, but we'll just have to wait and see. Hope it's sooner rather than later.