From my read of the post.
You're confusing PHP with MySQL
Magento Supports PHP ver. 5.5, 5.6 and now 7
It only supports MySQL version 5.6 (Maria DB too)
However the following packages replace it: mariadb-server-core-10.0 mariadb-client-10.0
sudo apt-get install mariadb-server-10.0
http://blog-en.mamp.info/2015/07/how-to-use-mysql-5-6-with-mamp-and-mamp.html
I found one link but this is for mamp server
