Hi,
this thread is just a bug report and should be may fixed in future versions.
I’ve been using Magento CE 2.1.2 and not the default MySQL port additionally.
While installing all files, the installation wizard uses the default mysql port 3306 but I did provide port 2418 at the SQL step, e.g. 127.0.0.1:2418.
The MySQL installation step could successfully establish a MySQL connection to my SQL server which is bound to port 2418, but the main installer uses the default port instead of the specified one.
Edit: Just did test it with the default 3306 port which works fine for me now.
Sincerely,
- Chris