ASP.NET MVC 4 – CMS / CMS Components (like WordPress)

I am developing a site in asp.net MVC 4 – code first, EF 5.

Areas of the site need CMS functions – but I need to drop MVC partials into the site – and would like to stick to MVC 4 (not MVC 2, or Web Forms, say).

Ideally slotting into an existing MVC 4 app – rather than taking over (but open to both).

Are there any MVC 4 ‘components’ I can drop in – or full CMS’s I could use?

Think ASP MVC 4 equivalent of WordPress.

Requirements include:

 - Free / Low price (< $99) / Open Source
 - Good SEO optimization 
 - Easily adding multiple images to a page, and laying it out
 - Adding new pages to the website
 - Editing Navigation
 - Friendly URLs
 - Tagging
 - Social Sharing buttons with appropriate page titles
 - Drafts and future posts
 - RSS
 - Blog + Comments
 - Polling
 - Contact Form
 - Google Authorship Integration
 - All text on site editable
 - Image Gallery, click for larger image, thumbnails
 - WYSIWYG page editing - and templating
 - User friendly admin tools (ideally not requiring technical / HTML / CSS knowledge)
 - Storing all of this in a SQL Server 2012

Thoughts on whether just using WordPress would be an big advantage? (I am semi-committed to MVC at this point – though if there are huge disadvantages may be persuaded to change).

Thanks