In which situation would a data controller most likely be able to justify the processing of the data of a child without parental consent?

SCENARIO
Please use the following to answer the next question:
ABC Hotel Chain and XYZ Travel Agency are U.S.-based multinational companies. They use an internet-based common platform for collecting and sharing their customer data with each other, in order to integrate their marketing efforts. Additionally, they agree on the data to be stored, how reservations will be booked and confirmed, and who has access to the stored data.
Mike, an EU resident, has booked travel itineraries in the past through XYZ Travel Agency to stay at ABC Hotel Chain's locations. XYZ Travel Agency offers a rewards program that allows customers to sign up to accumulate points that can later be redeemed for free travel. Mike has signed the agreement to be a rewards program member.
Now Mike wants to know what personal information the company holds about him. He sends an email requesting access to his data, in order to exercise what he believes are his data subject rights.
What are ABC Hotel Chain and XYZ Travel Agency's roles in this relationship?

Which of the following countries will continue to enjoy adequacy status under the GDPR, pending any future European Commission decision to the contrary?

Under what circumstances might the "soft opt-in" rule apply in relation to direct marketing?

In addition to the European Commission, who can adopt standard contractual clauses, assuming that all required conditions are met?