The SCIM protocol is
Solution: An application-level SAML protocol
If you want to remove an attribute's value in Okta, for example a value coming from AD that is not useful in any way, you have to:
Solution: Delete the mapping by the help of which the value came into Okta User Profile
Regarding policies, Okta recommends:
Solution: To have one policy rule per application, as more will most probably alter the behavior too much and you may miss important behaviors
Regarding policies, Okta recommends:
Solution: To include a policy rule that catches not wanted behaviors as a first priority and then label others for permitted behaviors
Regarding policies, Okta recommends:
Solution: Include a final catch-all rule that denies access to anything that does not match any of the preceding rules