[MOD IDEA] Creating Adaptation from an Original Story

Hey, everyone.

I am very new to Fallen Enchantress, and I hoped to recreate a story I'm currently working on within the game. Heck, I've conceived volumes about the world of Dragonsong, the story I created. However, not everything I hoped for was within the game. So, cut to the chase:

Dragonsong is a story set in a region known as Eteru, in which two massive kingdoms are recovering from a recent war with one another, and a new war is on the horizon. The story's protagonist is David Claus, who's half-human, half-dragon linage makes him the fabled Dragonsong, a prophesied hero who would save the planet from the Bringer of Purity himself. He has the ability to change between his human form and his dragon form mostly at will. However, when his home was destroyed by the forces of Etstal, one of the major kingdoms, he was forced to move west, to the city-state of Galmora. However, in a sudden twist, Ashensol, Etstal's contender, moved to kill the young dragon before he was too much of a threat. Etstal gained a change of heart, and moved to stop Ashensol from achieving their goal. David has no one he can trust beyond his close companions, and is unsure as to what to do next. As things turn for the worse, however, he must make a choice: go alone and possibly get killed by Ashensol's Elven Assassins, or to help his town's butcher's to fight against Ashensol, the latter proven to be far worse.

Now, here's the dilemma: David is a half-dragon, with the ability to shapeshift between two forms. There are no abilities in FE:LH that allow for this effect. So, I was hoping to find a mod that added this ability in, with a separate menu in the Character Creation screen to customize how the Dragon looks.

I was thinking that the ability is unlocked by selecting a custom profession, giving a small bonus as well as the Dragon Transformation. In Dragonsong, Dragons are more like Bipedal Wyverns than European Dragons, however, the mod could be just a fancy-looking Dragon with custom clothing sets. Also, in Dragonsong, Dragons are not enormous, definitely bigger than an elephant. David is only 12 in the story, so he's quite a bit smaller (about 3.57 meters tall in Dragon form). Then, of course, balance:

Advantages:

Dragon form grants increased health, armor, and damage to the user, and casts fear upon final cast in battle. It also grants elemental breath, a swipe attack, and extra magical abilities. It also grants an immunity to prone. The effectiveness of the transformation would scale with level.

Disadvantages:

Dragon form takes two turns to cast in tactical (although the transformation in strategic view is instant), and Dragon form isn't as strong as full dragons in combat. They also can't wear any equipment, use items, or change back to human form for several turns (again, freedom to transform anytime in Strategic view). They can, however, switch between ranged and melee damage without wasting a turn. 

Another thing I want to mention is that, in the story, the Dragonsong is weak to the ultimate dragon killer: Shadow Web Toxin, which negates all of a Dragon's abilites, including the power to shapeshift. This could lead to some interesting gameplay involving poisons as an extra advantage against dragons, creating "dragon-killers" in-game. 

If you have the time, you could also add other shapeshifts to the game in the same mod (or as an addon), adding the shapeshifter profession/class. As for the Profession of the Dragonsong-type character: Dragon Lord.

What do you guys think? I have absolutely no programming or modding experience, so, unfortunately, I can't give how it could be done. Will someone help me?

-Draconic Gaming