At first glance, 1714 looks great.  I hope to merge it tomorrow.

On the issues you raised:
1. I want to leave existing constants alone for now.
2. There are two 'create widgets' styles: create, place, create, place, ...; and create, create, ..., place, place, ... .  Both have their logic, both are used in IDLE.  The first makes sure that everything created gets placed.  The second makes it easier to arrange things in relation to each other and to rearrange.  I naively started with the first, but it seems that most experts advocate the second.
3.  If the dialog were left alone, three helper functions could be a sensible refactoring.

However, a alternate design could have links with standard blue tagging instead of buttons.  For example, the current About Firefox box has these 8 links: 'What's new', 'Mozilla', 'a global community', 'Make a donation', 'get involved', 'Licensing Information, 'End-User Rights', and 'Privacy Policy'.  This would make code much shorter and the result would not have the issues above.