Is it possible to use (and its select option) inside a or does it only works within a component ?>
As far as i know it is not possible using ng-content, but you can provide parameters to the template. So it's possible to pass another NgTemplate, which can again be used with an NgTemplateOutlet inside the original template. Here's a working example:
Hello
World !
Actually it is even possible to pass multiple templates to the original template:
Hello
World