WordPress multisite with site- and user-categorization

Hello

I’m in the planning phase of a new project, and I’m currently investigating whether WordPress would be a good choice for a project like this.

The website for the project will basically consist of 3 parts.
The first part is some users. These users will need the basic information like bio and contact information, but will also need to be affiliated with some more special data. I need some kind of roles/professions, this could for example be dancer, singer etc. each of this type of user should then be assigned to 0 or more of these professions.
Each user should also be able to link to a number of external resources, including youtube videos and slideshare slides. This should be in a format so the resources can be embedded on the site. Again, each user should be linked to 0 or more resources. The last thing the user needs is a personal blog.

The second part of the site is larger entities, an example of an entity could be a corporation. These entities should have their own separate part of the site including a blog, static pages, external resources just like the users and preferably the possibility of having their own theme. Furthermore each of these entities should be related to 0 or more of the users defined above.

Another thing I need is a kind of categorization/tags. This categorization should be site-wide, and should be available to tag both the users and entities mentioned above, but will not be used for single pages or articles.

I will also need a “main blog” for the site, but that can probably just be set up as an entity. I will also need standard users with none of the functionality for the users defined above.

I was considering using WP multisite where each entity gets their own site, but I am not sure if this will work out when the users need to be available across all sites, and when I need to be able to categorize each of the sites in a common structure.

Do you think WordPress will be a good fit for a project like this, and can you maybe help point me towards useful articles and plugins that will help me make it all work together?