In the case of links, at least, I suspect that you're looking for the newer "link_list" parameter: http://www.tinymce.com/wiki.php/Configuration:link_list
Hard-coding the links in the configuration is the easy way, of course, but the "link" plugin is also clearly designed to accept a URL string in place of the list -- if it finds a string, it will make an AJAX request to the URL, and expects a JSON response in the same format as the link_list.
Now if only I could figure out how to dynamically update the contents of a TinyMCE 4.x ListBox...