Almost assuredly. Two mods cannot alter the same asset. In such a case, the mod that loads last will be the one to take effect, overwriting the mod before it. Such things can't be "merged". You can only merge things that affect different assets.
For example, the Triss hair mod vs. the hood mod likely both replace the entire "head" model of Triss (it's not an actual
hood -- it's a replacement for the whole head mesh [or at least what counts as the "hair" mesh]). So, someone would have to rebuild the hood mod, replacing the texture for that particular hood model with the auburn hair. In a practical sense, that would be a different mod.
If it still doesn't make sense, here's another example:
It's the same thing as Geralt's hair. Geralt doesn't actually have "hair". Each of the styles is a separate mesh and texture that replaces the active one. So, if I recolor the short version of Geralt's hair, it doesn't affect the long version or the pony-tail version whatsoever. Different meshes and textures. Nor can I superimpose the texture for the long hair on the short hair. It won't line up.
Most likely.