The Best Platform for a Community Website - SEO friendly - Blog, Membership, and Forum - All-In-One

Hi Warriors,

I want to create a website that will focus on promoting a business opportunity, using a blog and at the-same time having a membership section with a private forum.

The blog will be open to the public(for commenting) and search engines like any other blog, while the membership section should be able to operate like a full membership site with different membership levels, hosting downloadable products and pages accessible only to members according to their membership levels.

The private forum will be directly integrated to the membership section but accessible to the public(for reading only) and search engines. Only registered members will post and comment on the private forum.

I want these three aspects of the website (i.e. the blog, membership section, and private forum) to all function as one website but I don't know which CMS or web platform that can integrate these three aspects and still maintain a perfect SEO.

If you think WordPress can be integrated in this way with other softwares, please tell me how to go about it, and the most suitable theme to use.

Other ideas are welcomed.

Thanks for your contributions, I very much appreciate.

Njualem