Wedge makes a point of clarifying her behavior is all superficial in his statement that it's all an act. Probably comes from her original choice of career and needing to be cheerful and optimistic to be popular.
By the way, I'm replaying now. After finishing the game, the ending has me questioning everything I know about 7.
(SPOILER)Zack... did he survive? A lot of people on the internet are reporting that he survived due to a "change of fate" after defeating the Harbinger. However, most people are assuming this because he walked away with Cloud after defeating an army of MPs. The problem is that we saw him do this in the original game, in the animation, and in Crisis Core. Facing the army isn't what got him killed. Zack was shot in the back while tending to Cloud. Then the MPs continued to riddle his incapacitated body with bullets until they were sure he was dead.
Basically, what we saw in the ending is not clear evidence that Zack's fate has been altered. What is clarified is Biggs fate in the final scenes. Like Wedge before him, he wakes up in bed with a bandage on his head (that rhymed). Only member left up in the air is Jessie. One could say Biggs and Wedge were spared this go around because they're Biggs and Wedge. But who knows? There may be a sidequest in the sequel to find out what happened to her.
Speaking of Jessie, we find out her surname is Rasberry. Her father, whose name can be found on his security clearance, is Rowan Raberry, a possible reference to the NPC of the same name in Lord of the Rings Online (or just something they didn't know existed).
There are a lot of references in this game insomuch as the Compilation goes. The "assassination attempt", the bike fight with Roche, Banora White, Type G, Kunsel, Avalanche HQ, hints at geostigma, the "edge of creation" mentioned by Seph at the outskirts of Midgar could be a shoutout to Edge City, Cloud/Seph's showdown.
For those who doubted, I'm pretty sure they'll find a way to include Genesis in the sequel.
At one point, Tifa makes a gesture I've noticed a lot of the stereotypical "cute Japanese girls" make in anime and other Japanese media. It's like a slight raising of one foot and one hand almost to their eye. I can't totally describe it without seeing it again. Seeing it took me out of the moment though because suddenly I'm made aware of just how Japanese Tifa really is because I've seen NO other culture in the world make this pose. Only "cute Japanese girls". Not to say I'm bothered. I like Japanese girls. This one aspect of their behavior is just weird to me though.