Replace a default model? Possible as MOD or only as TC? (Total base character replacement)

So I’ve put together a total character replacement set of assets, I have all the art all using the appropriate skeletons etc, everything works as a Total Conversion which I did for ease of testing on my end. I could pretty easily re-structure everything to function out of a mod folder which would be preferable, duplicate my created assets over etc however, the missing piece of information that I can’t seem to find anywhere is how to force a default model to use a new piece of art. Everything uses the same skeleton used on the main model so there shouldn’t be any errors or conflicts, I literally just need a way to say “hey use this instead”.

There’s plenty of information on adding new items to the game but is there any way at all to force the game to reference a different model for default assets as a MOD or must it remain a Total Conversion? If so the idea would be to point the Human_Male_TPV to my updated one, all the hair to my updated hair etc. Doable? not doable? Thanks, here’s an image of my working character conversion so no one thinks I’m crazy, new is left, default is right.