Site reorganization-proof internal linking via shortcodes, referencing page/post IDs.
Yes, the links generated by shortcodes will auto update themselves so you'll have no broken links.
Yes, posts with a custom type will be listed in the results when searching for a shortcode. The plugin will also add a shortcode search box to any 'Add New' or 'Edit' public custom post type page
Yes, using the shortcode [link id='123' text='my link text'] will produce a link of the following my link text.
You can also add class and rel attributes to the shortcode. [link id='123' text='my link text' class='my-class' rel='external'] will produce the following link my link text
Both of these examples can be viewed in Internal Link Shortcode Lookup box by clicking on the '?'.
That about does it - enjoy!