Hey Raziel, just a thought but to have compatibility with mods that add units you might want to change how you add the Reward Metals (RM).

From looking at what you say you edited it looks like you are adding the RM by adding it to each unit from the Units_Culture and Units_Wildlife. If you add it to unit type in the UnitType_Definitions it'll give compatibility to mods (I've tested it myself and it works but I don't want to upload a new mod that does that same as this).

Also to fix the HP icon issue that's in:
Tiers_UnitProperties -> Unit Upgrades Tiers - Tiers

Just need to edit each tiers medal rewards. You'll need to make an rpk file to add past +12 though as base game only has that as a max for HP Bonus. That's in same rpk under: Unit Upgrades Tiers - Level Up Rewards, just in case you needed to see the original file.

Anyway that's just my thoughts, it's your mod so I don't want to tell you what to do, so use the above information only if you want to.

Cheers and thanks again for all the mods you've done, keep it up!