I'll weigh in on the Stella/Luna thing. Let's review what's actually in the trailer.
At 1:35 in the trailer, we see the car driving at night, with the following voice-over:
"Turns out Luna is in Altissia. I trust she's well."
Next, at 1:40, we see an entirely different scene (red apocalyptic background), with a different character speaking:
"Your date's already waiting for you."
Then, at 1:45, we see the blonde female character, with two male voices speaking:
"She say anything else?"
"She's got something for me."
These feel like three unrelated snippets of dialogue (certainly the visuals are from three unrelated scenes), with no indication that "Luna" refers to the character that appears two scenes later. Count me in the camp that says Stella is still Stella.
The person in the new trailer is definitely Luna. Even if they're the same person, this much is definitely true.
You are aware that a person can take off one piece of jewelry and put on another? Not to mention that the moon necklace also has a star on it.