"Blank" or "Template" FFVI rom, Disassembly question

That kind of work would be counter-productive in most cases. Blanking events removes things like transitions between maps and other things like event bits the game needs to function properly. I'm no expert on events, but I'm pretty sure you would end up with a lot of gaps where the events would have to be left in. You would end up with only marginally less work to do than if you started with an unhacked ROM and just used the documentation already available and worked from there.

As far as the Sonic-esque interactive building mode; that's pretty much off the table. The maps are hardcoded and making an editor of sorts would required turning almost the whole game into variables. The editor alone would take up most of the ROM, then trying to get event code to work on top of the dynamic maps? not happening. Again, you are better off using the tools already available for map editing and learning event code.

If you want a complete dissasembly, download snes9x and disassemble it yourself. As far as disassembled and interpretted work: most non-compressed, non data code has already been commented on and put online by bank. As you do your own hacking... add your own comments.

Bottom line, there is no shortcut when it comes to real in-deapth rom hacking. But FF3 is probably the single most well-documented and supported SNES rom out there, second only to maybe Super Mario World.

Good luck! Hope this "helps".