Coding a 2D JRPG?

One of my long time goals was to write a simple, modular 2D JRPG engine in C; and then write modules to handle assets, scripting, and mechanics similar to my favorite FF games. After that I would write scripts to rip the assets from said games and format them for use in my engine.

Does this seem like the right way to do a clone? There is a lot of potential for engine reuse between FF 1 through 6, though combat and menu sub-modules would differ.

I don't have things set up to do this right now, but it is in my 2 to 4 year planning horizon. I just want your thoughts on it, and to see if it makes for interesting discussion. I'm especially interested in discussion of how these games are structured.

If I understood correctly what you want, I think it sounds similar to what I'm doing. But I'm using GameMaker and it's based on replicating things from scratch instead of figuring out ways of using existing routines from other games.

I started out creating a very flexible menu/combat system modeled after FF6, then I started adapting different FF characters into it. So far I've gotten FF1 (a white mage), FF7(Cloud) and I'm working on FF15 (Noctis). Also got Terra in it. 


I'm a coding rookie and this is my first big project. It's probably because of my inexperience that I'd say man this thing moves away from being simple fast. When I first started I had these neat systems to handle menus, targetting, processing commands, character stats, etc. Then as I replicated stuff from other games kept coming across edge case after edge case, things that required turning my systems upside down.

It's coming and getting close to a demo release. The ultimate goal is adapting every main character from the series as they are and some memorable dungeons and bosses from each game. But I think about all that and it's exhausting. I've been working on this on and off for three or four years maybe? I guess putting everything together would be a year, and all I've got to show for is one boss (Kefka), and four characters with a handful of spells. 

It's tiring ripping stuff, replicating animations, coming across edge cases that laugh at all your assumptions. I learned a lot doing this but it's coming to a point where I'm thinking "shouldn't I be working on my OWN game instead of doing something that's going to get me a cease and desist letter?". 

I could use some help though, if the helper doesn't mind a) using gamemaker 2 and b) learning all the code I've created.