I guess it depends on whether you are using the dataAssist pages as plugins or theme pages, or both, and why you are using themes or plugins.
1 and 2 from your example should work. 1 would be when using themes, and 2 would be for using plugins.
If you are trying to take full advantage of both themes and plugins in your site, then you would probably already have pages created with a theme, and pages based on your theme template and you'll want to plugin the data-assist forms into the content regions... this would mean you want to use 2.
The dataassist wizard isn't really designed with plugins in mind... which shouldn't be surprising since framework builder just came out. The server behaviors are flexible enough be applied properly to work with plugins, but by default dataassist wizard is really designed for a specific scenario because it sets things like links and redirects to the page names it creates... since the pages could now actually be plugged in from other pages.
The wizard will set the redirect pages to the plugin page, since it won't know you are using it in a plugin context, which means you will have to update the page redirects in the various server behaviors and links on the resulting pages to go to the page it was plugged into instead of the plugin page itself before it will work correctly as a plugin after running the wizard.
