You can customize other people in your party through multiplayer. All you need is a friend (or friendly stranger) who also has the game who are willing to help you.
1. Start a multi player game, customize the charactes how you like.
2. Start the game, save the game.
3. Leave the game.
Now you have a save file with two customized characters that you can play as a solo adventure whenever you like.
With that said it would be nice if there simply was a siungle player option to customize the other characters.
Perhaps you could even be allowed to jump into a character creation screen for people who join your party?
You can actually do this solo too, someone posted a guide.
http://steamcommunity.com/sharedfiles/filedetails/?id=769494798
