You have some great ideas for abilities here, and I don't see (though admittedly I only read up through Rydia) anything that would be impossible - most of these ideas seem well within the capabilities Grimoire LD and myself have developed over the past few years - but what you're suggesting is definitely a task for somebeody with advanced knowledge of SNES assembly. I would say either 1) shouldn't be attempted by a beginner, or 2) a beginner should expect a project like this to take at least a couple of years to finish.
For my part, I can't really offer much help with the doing because I need to focus on
my own project, which combines a ton of the "boring" stuff (it's a sequel to the original, so new character identities, new story) with a fair amount of the fun stuff (limit breaks, blue magic, a mimic character, chocobo time trials). For a splash of perspective, I was a complete beginner when I conceived of the idea in late 2012, and to date I have a demo with about 4.5 hrs of playing time (working toward an eventual goal of a full-length game).
I'm not trying to discourage you, by the way, if you're serious about getting this dine, I'd be excited to see your progress, and I'd be happy to lend advice along the way. Given the amount of work something like this would require, though, I can't imagine you'll find somebody who says, "yeah this is a great idea - I'll start working today." I think you're gonna have to be the one to actually do the doing.
A couple of pieces of advice to begin with: start living and breathing FFIV now. Lift up the hood and start seeing how everything works. A lot of that has been done by Grimoire LD
here. Study his disassembles, while keeping
this open in a separate tab for reference to what all the assembly commands mean. Doing that will help both knowing how the game does stuff and how FFIV does stuff. Both will be important to learn. Grimoire's thread there and mine
here both contain a fair amount of examples of custom stuff that have been added into the game along with specific explanations of how they work. Those should also be useful to you.
Download Geiger's SNES 9X Debugger and a good, feature-rich hex editor. Those tools will be entirely necessary eventually if not right away.
Also, consider an option other than adding a new window at the end of battle. Unless you have a very advanced knowledge of how SNES graphics work, putting windows in where they weren't before can be really difficult.