Is it mandatory for one user to be assigned as a Resource in order to have access to Contract Module

Summary: Is it mandatory for one user to be assigned as a Resource in order to have access to Contract Module?

Content (required):

Below are my Questions:

a) After Assigning the relevant Contract Roles in Security Console, if the users need to have Contract Administrator/manager/team member access or simply need to be added as Contacts in the Contract, is it required for them to be defined as resources in the Contract organization?

b) For the users to have Contract Administrator/Manager access, after assigning the relevant roles in Security Console, is it required to add the Resoruce Organization and Role in the manage Users Set-up and Maintenance task as well (like highlighted in the below screenshot) ?