
Have &, I'm not sure (since I don't work for EA) but I think that the reason that you can't change hair color per outfit is that it is tied to genetics. 'Change sim' and 'plan outfit' will open the editor so you can change hair, edit outfits, etc.).
In case you are not aware of any of these options, you can change outfits just by clicking on the sim when active and choosing 'choose outfit', you can also do this by clicking on a dresser or mirror (where you can also 'plan outfit' 'change sim'. Unfortunately this will revert back to the everyday outfit after they shower, etc. clothes like an everyday outfit and change to one of those. When you are playing the household you can always click on the sim and change to whatever outfit you want. It will also make you have some automatic everyday hair changes per season if you have seasons (There is a specific hot weather and cold weather everyday outfit for those seasons). You can go through and change the hair on each outfit.
The hair you choose for everyday should by default become your hair for all other outfits.
there! I don't use CC or Mods, so I cannot answer if there are options there, but as for in the game, I'm not aware of any way to modify/switch up everyday outfits to more than one at a time, but I can make a few suggestions of ways I have used to switch things up in:.