Help with making custom 3D armour

I am trying to make a chainsaw-man mod (if anyone knows what that is lol) and I figured the best way to overlay a new model over the player's is custom 3D armor.

The model will only use part of the player's so i disabled the leggings and boots and only modelled the head and arms.

I googled a tutorial and tried to follow it for my own use case with no success.

My steps so far:

1. Import the player model from CEM template loader.

2. Model over  the player and texture

3. Delete the unnecessary player model

4. Convert into a modded entity 

5. Export as a .JAVA file

6. Save both the layer 1 + layer 2 textures

7. Import all the above into MCreator and skip the animation 

8. Create a new armour and add random images for the items as placeholders

9. Choose the model and configure it

10. Save the mod element to be greeted by this error. 

Images for reference:

Model (yes, i have setup the origin/pivot points)

Armour element inside MCreator (Page 1)

Armour element inside MCreator (Page 2)

I have painted directly over the model in Blockbench just so you know

Thank you