can someone please identify these characters

[Lusavari]

It's fan art. Lot's of people imitate Tetsuya Nomura's style. Don't forget how legit the fake Kain and Lightening announcements were as DLC characters for the first game. The article tells you there's no official roster yet, which should be enough to tell you that's fan art.

Another clue as to how that's fan art: Stella and Noctis are on it. Why didn't they put Lightening in the first game? The official reason was because they didn't want to create any preconceived notions about her fighting style, i.e. they didn't want to spoil the FFXIII battle system or story in any way.

You're third clue: They wouldn't announce that many characters so quickly.