What you see in cPanel are the settings applied to the private PHP installation that serves cPanel itself. For the other settings you need to consult your host. They will either have to change the php.ini file of their server OR give you instructions to create a .user.ini file on your site's root with the custom PHP configuration options.
Please note that the PHP settings which are not ideal are optional. You don't really need to do anything about these two (even though Joomla's installer says otherwise - and we're copying that information verbatim from Joomla installer). The display errors settings is overridden by Joomla with its Error Reporting feature in Global Configuration. As for Output Buffering, Joomla turns it off anyway and uses its own buffer system. So just ignore these two settings, your site is going to be just fine.
Nicholas K. Dionysopoulos
Lead Developer and Director
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