If his heartless does show up then that means that Lea can't come back. Well, I guess it could if the game is before KHII. It's been stated that if the heartless is destroyed then the nobody the person becomes complete. The person can't come back if the nobody is destroyed and then the heartless. I do want him back though. He's one of my favorite characters.
No, there isn't a problem with it. In my opinion, however, there are more hints that Sora is interested in Kairi more then Riku. Riku he just sees as a brother.
I think that's more of an opinion. I've never heard that there is a difference. Since I was a kid I've always called myself a girl gamer and I never used my sex to get attention or anything of the sort.
Just because Sora searched every where for Riku doesn't mean he's gay. They have been best friends since childhood so of course Sora would look for him. If my best friend went missing then I would search every where for her. That doesn't mean I'm in love with her and want a relationship. That's just what friends do. And there are strong hints that Sora has feelings for Kairi. And Kairi has feelings for Sora.
I would look for other people and try to figure out what happened. I don't have the guts to kill myself. I would try to survive as long as I can and hopefully find a way to fix whatever happened.
I don't wear heels. I think I've only worn them 2 or 3 times. Even when I wore them to a dance I took them off five minutes after arriving. Heels are uncomfortable so I refuse to wear them.