Changing Sabin's Blitz moves?

Is it possible to alter Sabin's blitzes?

For example, replacing something with Blizzard Fist- the attack Vargas used?

If I'm guessing correctly, there can be only 8, but that shouldn't mean I can't change them...

Anyone try something like this?

You can change anything like that about the Blitzes using FF3usME. You probably won't be able to make Blizzard Fist in exactly the way you're thinking, because that animation is part of a battle event, but you can make something similar. You can make a new button combination, different properties for the attack, a more fitting animation (though like I said, not the same as Vargas', maybe more like the Blizzard spell or BaBaBreath animations), and possibly cause it to work like Sneeze (but fail on enemies immune to instant death) all using that tool.

I figured I couldn't make it exactly, which is fine, but could I just use that editor with whatever ROM? This sounds really fun- and I have to say I'm extremely happy to become part of this community!

Yep! Just download the editor, ROM and emulator and you should be good to go. It may take some time to find out how to alter each thing that you want, but I think everything that you want there is in the editor.

And welcome to the community for sure!