To email your junior contacts, you can do this through their parent or guardian profiles in the contacts module. Head to your contacts module in the admin area to send emails to your junior contacts.
Note: If a contact has the junior flag (above) and has a linked parent/guardian, the email contact button should display (like below) in their contact profile. Which if selected will send an email to the parent/guardian of the junior.
On the main page of your contacts module, filter your junior contacts from the contacts table, this will bring up only those who have the junior flag applied.
Then select the email button, and their main contacts(s) should appear in the recipients' list.
Note: Emails will be sent to the parent/guardian and not sent to the junior.