WMPU Organizational Structure

Hello Everyone:

I've added an attachment to help with this question....

Do I need to install WPMU on the "Special Child" website so that it's standalone, or can it live as part of the parent company's organization?

If the "Special Child" website needs to have it's own WMPU installation can the user profiles be synced between the "Special Child" and other parent organization's websites?

IF the "Special Child" can indeed live under the parent organization's web structure can all users come to "specialchild.com" and get a username and account such as "specialchild.com/xxx" WITHOUT seeing anything from the Parent company?