At the moment, it’s hard for Japanese cosplayers to contact original creators to gain permission to cosplay their characters.
While at the moment there has been no laws or amendment proposed to current Japanese copyright laws or any overseas laws, but the current ruling party of Japan is expecting that cases could arise in the future that may test current laws and want to get ahead of them.
At the moment, if a cosplayer is participating as a hobby, without making any money, there are no laws being broken.