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.