Data Pack- Custom skins or Armor

Hi guys!

I am working on a vary cool project for a Museum and I am trying to put a quest system in a Vanilla map, built for this purpose. I am getting quite good at Commands, so the quest thing is going good. My main concerne is I want to plavce two idle armies in front of each other, to represent a 18th century battlefield.

My first idea was to generate villagers and apply new skins on them but that last option seems impossible in Vanilla. My team developped some very cool skins I would love to use, but after wathcing hours of videos on Youtube, I can't figure how to do this.

I thought about putting a skin on an amormor stand, but i didn't suceed to find how to craft a custom armor of that type.

I* am stuck and I need your help. Is there any way to modify an armor and apply a skin on it in a datapack? Or change the skin of a mob/villager to make it look like a player?

I would like the people to have the modifications when they download the world so datapacks would be the best.

Thanks a lot for your help.

Sorry for my English: i usually speak French.

Sam