Hi Joe Lipski,
A Tableau Online Site Administrator can be a Creator but they are not required to be. Per the article you linked, the Site Admin can be set to either "Site Administrator Creator" or "Site Administrator Explorer."
However, based on the licenses you have purchased, since you do not have any Explorer seats, the Explorer role would use up one of your available Creator seats, as any site roles assigned in excess of what you are licensed for will attempt to use a higher seat available. For example, if you assigned 8 users to the creator role and 1 user to the explorer role, that would use up all 9 of your creator seats because the explorer role would use up the higher creator seat. There is no option for Site Administrator Viewer.
Additionally, the Tableau EULA requires that each named user be assigned their specific license/seat. Assigning a creator seat to a user who does not have a matching Desktop Creator license would not be in compliance as the license would be shared among multiple users rather than the single named user.
I would recommend discussing further with your Tableau Account Manager so they can review your use case and how many users you will need.
Hope this helps!
Senior Technical Lead
Tableau Server & Desktop Certified Associate