If anyone wants to take a look at porting it over, feel free, I don't really know my way around the inventory/AI files and they're definitely important. Inventory files don't play nice right off the bat either, since it turns all the weapons invisible. I used to play Dead Island alot on Xbox360 and wanted to have some fun with the newer version on Xbox 1 with some modded weapons. The AI file seems to somewhat work, with the correct damages and enemy reactions, but zombies can swing at the air and hit you from 5+ feet away, so it might be another numebrs conversion thing. While the skill trees, loot files, and random enemy progression stuff seems to have worked (getting random zombies from my level all the way up to 100), I have no idea how to fix the AI or inventory files. There are multiple blueprints throughout the game which the player can obtain to modify existing weapons to.

My first copy over ended up with me moving so fast I hit a wall and died instantly. Mods are used to upgrade weapons in Dead Island. One thing to watch out for if you're copying them over is that things like movement speed, jump height, etc seem to have been converted to use much smaller numbers, averaging between 0-5, while I think the original game and many mods use numbers between 100-1000. The skill trees and enemy leveling seem to have ported over fine. I was able to port over a decent amount of Director's Cut Deluxe Mod Edition. Just an update, modding does seem to more or less work.

Dead island definitive edition mods