There is no official guidance on this, so this list comes with no guarantees. However it is the closest I got to enabling MCC without forcing an admin role on connector user in SC.
While this solution requires the least effort to implement, since it’s not officially supported by MC Connect product, and it's implemented upon your responsibility, there’s a risk that it might stop working in future releases, preventing new Journeys from activation (running Journeys won’t be affected). Therefore, monitoring and testing of new MC Connect and Core Platform releases is required.
- Author Apex
- Modify Metadata Through Metadata API Functions
- Manage CRM Content
- Manage Translation
- View Setup and Configuration
- Manage Custom Permissions
- View Roles and Role Hierarchy
- Customize Application
- Manage Sandboxes
- Flow User on each Integration User record
This set of permissions assigned to Integration User record would allow to activate MC Journeys that use Salesforce Data Entry Source while respecting the sharing rules configured in Core CRM, so that we don’t get any duplicated data syncing to each Business Unit.
Journey Builder Entry Source filters by Market field are still required to prevent communications to wrong contacts.
Above permissions are in addition to standard MCC permissions: ConnectedApp, Marketing Cloud for AppExchange User/Admin