Question

Is it possible to set the path and domain one time at the beginning of the script and have all future sets conform to the same?

From the docs:

 bool setcookie ( string $name [, string $value [, int $expire = 0 [, string $path [, string $domain [, bool $secure = false [, bool $httponly = false ]]]]]] )

Answer 1

sure:

function own_setcookie($name, $value, $expire=0) {
    setcookie($name, $value , $expire, 'myPath', 'myDomain');
}

then use:

own_setcookie('myName', 'myValue');