It doesnt matter, since like before, you can only participate once per SE ID. Unless you bought several copies of the game and registered each character on a difirent ID, having one main and 15 mules is going to do exactly as much as having one character available to you.
Other contests, including the original SE account contest, and that one we had in 2012 for the JP vanafest were limited to one winner per SE account. When you entered, you had to fill out a survey online and also designate which prize you wanted and which character you wanted to get it.
Bonanzas are completely different, as you can enter up to 10 times per character.