Work on completing the journal and leveling up. I'm also at that point.
When you defeat Sephiroth, Tifa gives you the Fenrir Keyblade.
No. Just No. Sephiroth is to purely awesome.
Yes.
Yes.
If Sora can, anyone can do it.
Unfortunately, I doubt it.
No.
Absolutely he would defeat him in one attack.
The BEST keyblade is based on opinion, although the strongest (in terms of strength) is the Fenrir Keyblade, obtained after you defeat Sephiroth.
Yes.
Defeat Sephiroth.
The best weapons are The Ultima Weapon and Fenrir. You have to synchronize The Ultima Weapon and you need to defeat Sephiroth to get Fenrir.To Sync the Ultima weapon you need a lot of items and I suggest you look up some sort of guide online.