If someone fills in a 'Contact Us'' form, and we send an automatic response that the message was received and that we will get back to them, do we need the unsubscribe text at the bottom of the autoresponse email?
No, that's considered a transactional email so technically it doesn't require an unsubscribe link. The email should also be allowed to be sent to someone even if they have unsubscribed from all other marketing emails.