Just wondering if I can create a this rule:
1) check if a node (when viewed) has the translations for all enabled languages.
2) If the it doesn't, then create the translation (for all enabled languages)
Out of the box: no.
If you are willing to code, check the rules API. It lets you add your own conditions and actions.
If you don't need any of the rules functionality you can of course just implement hook_node_view.