Curseforge Power (origins) Transfer and Modding

What I am trying to do is find someone who is willing to take the pre-existing Curseforge Mod of Minecraft Origins, have a few tweaks around it to change its capabilities to match other mobs more closely (like the enderdragon and evoker and wither), and transfer that mod into a early version of minecraft (1.12.2). This is for a Minecraft ARG that I myself am currently writing, but i need someone who is experienced in mod making to either change the preexisting Origins mod to have different abilities for the player to have and change its version to an earlier version, or recreate the origins mod from scratch (-taking reference from the original origins mod is okay too-) with different abilities and classes that are interchangeable for the story. (also make sure it can work even with old laptops from 2018 and later)