Need help figuring out where I am

I was playing ffvii (og) a few months ago and put it down. Now that I’ve picked it back up, I don’t remember where I am supposed to be going.

What I’ve gathered is: A party member has died. I don’t know how recently. I have the airship and sub. There’s a purple ball in the sky. I have Neo Bahamut. I vaguely remember Chocobo raising and racing. Characters about level 58. I can’t access the area at the extreme north (airship gets bounced back)

If you have any suggestions on where to go, I’d love to hear them.