I don't think I'm gonna use my extra characters. Using the extra characters for yourself, probably isn't the way Nintendo wanted you to use them
I won't make my other characters straight away either. After I make some big progress, I will made the first extra one.I probably won't be making the other three characters, unless I have nothing better to do after making a lot of progress in the game. Like after I've fully upgraded and furnished my mayor's house, done a lot of community projects, gotten all the shops, captured most of the bugs and fish, etc.