NamelessMC

This doesn't have to be a real Minecraft username, to change the text you can edit custom/languages/language/user.php and change the term for Minecraft Username.

You can disable Enable nicknames for registering users? in the StaffCP -> Configuration -> General Settings tab, and then disable Force premium Minecraft accounts? in the StaffCP -> Integrations -> Minecraft -> Account Verification tab

Hi,

Which addons have you installed?

Hi,

You're right in saying the Google Analytics script goes into custom/templates/template/header.tpl, but you might need to add {literal} before and {/literal} after the script.

Hi,

If you haven't already, try enabling the "Unsafe HTML" option in the custom page settings.

You might need to re-paste the code into the source code again.