Creating a multisite with an organization site and many department sites

I'm planning on having many sites on one server. I would like the organization site to use one theme. I would like the department sites to use a single different theme between all of them. The departments should be able to change images like page header, logos, etc. The media library of the organization site should be available to all department sites. All the department site images should be contained on their own site. We have talented devs developing custom plugins for both the organization and the departments, so the sky is the limit.

Anyone have any general tips, plugin suggestions, comments, or warnings on implementing something like this? Anything we should use to make the user editing easier for them like Elementor or Avada?