@boopidoop Hi 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:
• The hair you choose for everyday should by default become your hair for all other outfits.
• You can go through and change the hair on each outfit. This will add variety. 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).
• When you are playing the household you can always click on the sim and change to whatever outfit you want. You can create your party, formal, etc. clothes like an everyday outfit and change to one of those. Unfortunately this will revert back to the everyday outfit after they shower, 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'. 'Change sim' and 'plan outfit' will open the editor so you can change hair, edit outfits, etc.).
Hope that helps some. Have fun! 🙂