Sephi was a breeze. I had some problems with Jenova Absolute or whatever form it was she was in, but that was it.

Ending's a real disappointment too, ain't it?

Anyway, it's been a year or dva since I've beaten it, but I can almost assure you my party was Cloud, Cid, and Yuffie. Yuffie used All Creation a few times, Cid kicked some major ass with skills, and Cloud just hit the crap out of Sephi. Needless to say the boy barely got off his second Supernova before he was a deader.