Thanks a lot for this project and for the research. I'd like to mention these FFIV themes in particular:
-"Sorrow and Loss"
-"Golbez, Clad in Darkness"
-"A Long Way to Go"
-"The Final Battle"
"Sorrow and Loss" is an arrangement of the main theme though. Golbez's theme could perhaps feature a real pipe organ if it's chosen for the album. "Mystic Mysidia", "Damcyan Castle" and "Another Moon", along with others I would have said, have already been mentioned.
For something newer, could orchestral arrangements for the Japan-only DS game Soma Bringer (
https://vgmdb.net/album/7032), or the Wii game The Last Story (
https://vgmdb.net/album/22773) be possible by any chance?