Creating-organizing my solution ASP MVC, merging from mvc and web site project

Creating-organizing my solution ASP MVC, merging from mvc and web site
project

I've been asked to consolidate multiple projects / types / HTML websites,
MVC under one solution
The issue is the project/sln types vary from ASP MVC 2, 3, 4 to HTML +
javascript websites. Details after summarizing the question below -
Question: How can I
Organize everything under one solution
Can I have a mix and match between web sites project types, and ASP MVC
project types?
What is recommended best practise (I'm leaning towards ASP MVC projects
across the board)
Is there an auto convert in VS 2012 from Html web sites projects type to
ASP MVC projects type?
How can I get membership [already implemented in one project] to
cover/protect the new projects], is this configuration or something
simpler. I.e. I need the membership to spill over and provide coverage to
the HTML projects, will it do this?
Or should I should I put everything in the same project, the functional
features are different, one does BI work, and the other HTML does web form
generation.
Details of project type:
HTML + Jquery UI + underscore, require + backbone projects [could use some
help in how this should be organized inside MVC]
ASP MVC projects with simple membership