i tried to do the same steps using an custom ped that i downloaded here. the thing is its hard to follow your guide.
To sum it up what i did:
Extract .ydd, .ytd of the ped using right-click on open format in OpenIV
.odd and .otd are created with all the extracted .odr and .otx files within the peds name folder
Now this is the part where it gets really confusing. In your post you stated I have to create more .odd and .otd to reference the .odr and .otx so OpenIV can convert the files into .ydd and .ytd.
So I did the part where I create for each .odr file .odd reference for e.g
-> creating "hair_000_r.odd"
within the .odd file I put:
Version 165 32
Now I did this for each .odr file (rename, then with in the .odd referencing the .odr did the same with the .otx file)
when I tried to load the game the texture looks janky and it didn´t fully replaced the ped. I also took the .ymt and the .yft of the chacracter and replaced it with player_1 (michael) but i dont seem to get it working.
I really want to get it working since theres no any other reliable way to permanent modding the single player character out in the game.