An update as I figured out somethings for myself:
dialog.js is not part of the core jQuery UI and thus isn’t available via the standard jQuery handle. I have found queuing it difficult and to differ in success over theme’s I tried. If it works it looks, to put it nicely, a bit crappy so that requires more work. I settled with jquery and used a regular form for posting new tags. I load the table via ajax calls that are available with the standard jQuery handle. For me this works better for now as it works on most themes and is user friendly enough for me now. Making it nicer is not worth the effort with dialog for me at this point.
I also used the wp_myaction_callback for admin only secure referrer callbacks for admin panel for which I use the WordPress nonce functions to do so.
Gr.