I've got all dalmatians, locked ALL keyholes, beat all tournaments with all its options, beat Ice Titan, beat Kurt Zisa. beat the Phantom at Neverland, and all there's left seems to be beating Sephiroth and getting the Ultima Weapon.
How do I get the Ultima Weapon? Just by walking around all worlds and getting the items to complete all the synths?
How do I get Curaga? I've only got Cura so far!
Is anything else to do in Kingdom Hearts, besides beating Sephiroth? ump:

To get the ultima weapon do all the synths then it should be the last one. to get curaga talk to aerith in the hollow bastion library and I think that beating sephiroth would be all you have left to do then.

Beating Sephiroth is no easy task for most people, but i managed to beat him 3rd try. Just as long as you can hit him before he does "Sin Harvest" attack and keep your life close to max you should be ok. Aero helps too.

Have you found all the postcards, and done all the winne the pooh things? Other then those two things I don't think there is anything else to do.

Yeah, Mike makes a good point. Not everyone notices but the winnie the Pooh place is considered a world and must be beaten to gt 100% completion. And when trying to kill sepiroth strike raid is a must have. IT can interupt sin harvest from a distance and you are temporarily invincible while using it.