Hi! I've just updated my Character Mod helper. Currently, your mod is always overwriting the default character. If miniMAXIme is used in character selector mode, the default character should be preserved so it can be selected as well.
If you'd depend on the helper mod and let it handle the character creation, your mod should work as expected with miniMAXIme (which I'm about to update). The helper mod contains info on how to use it and example code, so it should be quite easy to transition to it.
When your mod is compatible with miniMAXIme, I'll add an optional dependency on your mod so we'll have a central place to find character mods.