Drupal is a CMS, Content Management System. You create a template and the user can add, delete or update pages from their browser or any browser on the internet. No special tools or knowledge, it is all already set in the template. Drupal is Enterprise Class, it is very good for what it does... but it is meant for bug complicated web sites.
You sound like CMS Made Simple or Wordpress would be enough. But there are others... CMS (Content Management System) : Accessibility
Q2 - No. You can add Flash elements into the HTML and it will work fine. But it does not handle full Flash sites. For that the user has to know flash to make changes or the developer good enough to put all important info into a database so content can be edited but new pages and links etc. require new movies and you will have to do all that. Just one of the many reasons Full Flash web sites are a bad idea.