After talking with another engineer I was able to confirm that it’s not possible at this time out of the box.
You could theoretically validate the user after a login with a rule but then you stand the change of piling up users who haven’t been validated successfully.
I would recommend sharing your use case with our product team over at Auth0: Secure access for everyone. But not just anyone.. Each submitted request is read by our product team and help set the tone for the roadmap moving forward as far as features and enhancements. Thanks!