I really hate threads like this but what the hell...
For the sake of argument I am not even going to base my logic on game mechanics (cause it's stupid and pointless) so you can take your Particle Beams, Giga Galvatron, and Trance Ultima and stick it up where the sun don't shine.Back on topic...
The real question that will answer this is how the Final Aeon works, which is never showned or explained in the game so for the sake of argument we'll assume that the Final Aeon works through force (i.e. it's more powerful than Sin and can pentrate it's shield and thick hide). If it worked another way (though the evidence is seriously lacking) then this debate would be irrelevant.
This would dictate that force alone could beat him. Because of this, it's possible for Exdeath, Kefka, Kuja, Sephiroth, and the Cloud of Darkness could destroy Sin cause all of them either showcased enough power to decimate a planet on a large scale (something Sin seems incapable of) or by story explanation should have the power to do so.
The Palamecian Emperor is strong but even his power to create devastating Tornadoes wouldn't bother Sin, Ultemacia never showcased enough power to do anything other than bend time to her will but even then we never got a decent estimate of her abilities so arguing her validness is moot. The Undying doesn't showcase even a fraction of what Sin pulled off so we'll assume he would lose. Chaos is sorta've in the same boat as Ultimacia but overall he just seems to be strong and nothing else.
Zeromus is a completely different story though... We never get to see how powerful he is on a destructive scale but the whole story sequence about the crystal can't be discounted. The question depends on how you interpret the scene. Personally, I feel Zeromus was a spiritual being and Cecil using the Crystal gave him a physical form which means he could be killed. In his true form, Zeromus can't be hurt but like the other mentioned above, we don't have any clear evidence of the extent of his power so chances were he probably couldn't hurt Sin so the battle would end in a stalemate. If Zeromus was in his final form he could be beaten by Sin.