Correct, you need to tick every variable you want to be visible on OPC.
I also had to install a certificate to be able to get ignition to connect to the code sys OPC. Was just a case of right clicking and selecting add new certificate in the codesys software. I then came up against some issues getting security settings to work so Ignition could connect.
If you get into any issues, Id be happy to post some screen shots later on of my settings.