If details are changed on the Recurring Payment eg: Contact, Payment Form, Merchant Facility etc, does the linked URL token automatically update?
No. You will have to manually update these details on the linked URL token.
Alternatively, after you have made any changes, you can remove the URL token lookup on the Recurring Payment and uncheck the create URL Token checkbox.
Then edit the Recurring Payment again and re-check the Create URL token check box. This is will create a new URL token based on the current information on the Recurring Payment.