Intermediate Event Editing Video Tutorials

Ha I gotcha man, I just wish I knew where to start looking in the D banks, I mean there's no document for it and I've only found one JSR command in there so yeah that's a little tough.
And who knows, it could be compressed, they only had so much space on a ROM back then lolz.

Concerning the Iseria battle, ha I gotcha man, I was thinking you did that in game and whenever someone fought her, she'd literally speak in ZSNES. The only possibility I could think that would allow someone to do that would be to record your voice and convert it as a BRR and then delete FF6's instruments to replace them with your voice's BRR's.
Oh..
Lolz jk that'd be nigh impossible ha but hey it'd be sweet.

And yeah some Iseria music would be awesome, I'm fixing to look in to custom music, i play two musical instruments and can read just about any format of music so if I have a feel for this, I'll tell you and try looking into an Iseria Battle theme.
Ha if I could get a request for a song, it'd definitely be Rydia's theme!
You gotta hear it if u haven't:
http://ffmusic.ffshrine.org/ff4midis/ff4-midis.php
Scroll down to Rydia's theme, sorry the original MIDI link to the song wouldn't work :/
Pretty nostalgic sounding to me though
Well I think I've made my reply overly long :p
xJCSx

There's this youtuber that did exactly what you mentioned, He got mint's (from Tales of Phantasia)'s voice clip for First Aid and inserted it as an instrument into chrono trigger, his name is xjustin3009x. He also made either gabriel celeste's theme or iseria queen's for chrono trigger.