MaliciousCookies

You need to find out which changes were made to the file by individual mod authors, compared to the original clean file. Easiest way would probably be to write a script, or find yourself an XML comparison tool. Then you have to incorporate all those changes into a single file. There will be conflicts, as some mods will probably edit identical nodes, and you'll have to decide which one you want to go for.

\loc_XX_data.spk\font\font_config_mipmap.ini where XX is the language code for your set ingame language

I tried to do that by replacing hat models with random stuff, it dissapears, but leaves your character half bald.

It's not possible to make something like RaceMenu, since all the head models in the game are premade. All the model files are located in \datapc_initial.spk\equipment\huf\hea\ (female) and \datapc_initial.spk\equipment\hum\hea\ (male). You can edit the file \data.spk\items\equipment\library_equipment_pla_head.sli and add as much variations as you want, since the game doesn't actually care what you put in there. Then you put it in the CC in \data.spk\gui\preview\character_preview_library.sli. However, NPC head models seem to be fitted to clothes they're supposed to wear, so you'll experience a lot of clipping, seams, invisible body parts and so on. Stuff like hair and eyebrows actually behave like equipment, the game places them in invisible inventory slots. Color information seems to be stored in \data.spk\gui\preview\character_preview_library.sli