Guide on adding a new model, animation, and creature to HoMMV

I checked your file. I tested it on a vanilla version of 3.1 and on a clean NCF core. As expected, your file works correctly; the swordsman was replaced with a peasant in a yellow shirt. I can't help you any further because I can't fix something that isn't broken. The only thing left to do is:

Check how it works on a vanilla version; I'm not responsible for compatibility with various mods (although, in theory, there shouldn't be any problems).