The ending gives some closure to the plot, but still leaves much to the imagination. This is just what I figured would happen.

Terra: It should be assumed that Terra returns to the orphanage and helps to take care of the children that have helped her to learn the meaning of the word love.

Locke: Locke probably just spends his days "Treasure Hunting", and probably ends up with Celes.

Edgar/Sabin: Edgar and Sabin rule over Figaro together.

Shadow: Shadow commits suicide.

Cyan: Cyan works to rebuild Doma.

Gau: Back to the Veldt?

Celes: Ends up with Locke presumably.

Setzer: Lays the Falcon to rest and works to build a better airship.

Strago/Relm: I guess they return to Thasama and Gramps dies and Relms aspires as an artist?

Mog/Umaro: Mog continues to boss Umaro around in the caves north of Narshe

Gogo: Goes back under Triangle Island.