Hi,
If you know these users you could stub out the pages and features for each user and then create roles that let them edit the pages and/or create new pages.
mojoPortal is not designed for building social networking sites where any registered user can create content, it is designed for business web sites with content to be created and edited by trusted users. Users who can create pages and edit content can use javascript and javascript allows you to do lots of cool things but can also be used for bad purposes very easily, one should never let strangers add javascript to a site. The security requirements for building a social networking site are much different than what mojoPortal was designed for.
However the blog does not have a built in gallery, those are separate features. They can post images directly in a blog or they can add them to galleries and then link to the gallery from the blog. The blog also does not have sections, it is like all features it plugs into a cms page and it has some supporting pages it links to but they are not cms pages and pages cannot be added to the blog other than blog posts. You can create child pages beneath the cms page that contains the blog.
Hope it helps,
Joe