Hello phatair,
1. Yes, it is necessary to have Search Engine Friendly URLs enabled in Joomla Global Configuration
2. Yes, JoomSEF only works in Apache mod_rewrite mode; if that is off, then Joomla core SEO is used (regardless any other options set)
3. Yes, you can look into
documentation
4. This is of course not true. If paid component is done correctly, there should be no meta tags or footer texts.
Best regards
Pavel Gavlík
ARTIO Support Team