In light of the heightened attention now shining on The Bore dot com.
Let's dispel once and for all with this fiction that the Splatoon characters are under 18. They are absolutely 18 or older.
Additionally, squids go through puberty at a very young age, which allows them to create and expel 11 pounds of eggs. That is why even if there was a misunderstanding and the squids were under 18 in squid years, they would actually be middle aged adults in human years.
Remember, these are Nintendo characters, and Nintendo would never authorize anything bad.
I also call into question any claims that you can meet minors on Splatoon. There is no voice chat. There is no text chat. Shit is locked down harder Metroid Prime 4.