This has probably been asked 100 x before but I can't find an existing post about this...
Is there a way of allowing the Unsubscriber to provide a reason why they have unsubscribed?
This would require a memo field to be included within the Unsubscribe page
Does the redirect to our custom unsubscribe confirmation page provide the clients email so we can capture this in the mini survey form?
It doesn't automatically, but you can include the [email]tag in your redirect link to pass through the email address. Something like www.mydomain.com/unsubscribe?email=[email]as your unsubscribe redirect would automatically have the email address passed through.