Fair enough. 
Maybe you should give the reader the option to customize the characters and to not customize? Or you could let them customize one character each episode. First episode start with the mc and in the second episode you could tell the reader that they can only customize one character this chapter and have them pick who they would like to customize. Not exactly sure what the code would be for It tho
But at the end of the day. It’s your story. Your the author do whatever works for you. Good luck writing! Lemme know if you need any help with anything.