Yes you can. Just go to 'My Subscriptions' in your account and click on 'Change Flavours'
Yes you can cancel your auto-subscription by going to 'My Subscriptions' in your account and clicking on 'Change' under the payment details.
No, eBook subscriptions cannot be paused.
With a subscription you are entitled to 3 eBooks per month. You will be able to access these by logging into your Account and navigating to eBooks.