OH and POSTED!
PH will go again to finish up with his weapons.
Spear - I think he can throw this as Sephiroth hovers in place when casting meteor
The Pyramid's tentacle - Let's see some poor thing get it's face impaled!
As for Sephiroth, remember that the only Magic skills he has on the given list is Meteor and Octaslash. Heartless angel will instead be tossed to the side and substituted with meteor.
By the way, thanks to the beautiful Angelic, we have thought of some logical strengths and weaknesses.
Seph casts Meteor while hovering above/ standing but he is still in this moment. It obviously takes longer than just a split second to do so, so within that time, PH should have enough time to throw his spear to counter.
Although the Great Knife can be a sword-breaker due to it's massive weight ontop of strength, it is slow.
Here is the formula which gives it it's greatest strength I believe.
Weight + PH's str + gravity + Seph's str = possibility that sword breaks.(i don't think Materia had much affect on the blade but I could be wrong)
See the key here is Seph's str will keep the sword from steering away and thus it would be like putting two heavy weights on the each side of the blade to use to cut through like a wooden block.
It's obvious that from a distance, Seph has the upper hand(unless the spear gets him) while up close, PH may take the win thanks to the tentacle. (swords being locked and then boom! impaled by that thing).
However... we shall see! I'm still thinking of a way we can calculate this... but idk.