The Japanese site has icons for every Type in its code. It doesn't indicate that those have to be the Starter's Types, especially since those Types don't match the designs of the final Evos.
Also, water isn't inherently feminine, and mercury (named after the greek GOD of the same name) certainly isn't feminine.
Maybe the final evos are every type. ( ͡° ͜ʖ ͡°)