1. No, webpages are just small php-like (with Razor) script files wich turn out html.
2. Web forms is the 'old' asp.net technology, their versions distributed with the .Net framework. MVC is not part of the .Net framework. Web pages are just dynamic html with no serverside controls and no MVC.
3. Often you can convert the solution, do some small changes and recompile. Unless you have done some seriously freaky stuff.
4. It's a pattern, wich seperates logic from UI. It provides you with a unit testable way of writing asp.net application, while the designer can do his magic in the frontend pages.
5. Web pages.
6. MVC, it's the shizzle. No more page lifecycle, web forms are too loose for enterprise development, good for a hobby or small pet project, but not for 'real' apps.