All answered on the Adobe website
1) Refer https://creative.adobe.com/plans
2) Yes, if you subscribe to the month-to-month option but the monthly fee for that option is higher than a full year membership.
To cancel a one-year membership, you need to contact us. If you cancel your membership before meeting the 12-month commitment date, you will be charged 50% of the remaining amount left on your contract.
3) Yes, you get Photoshop CS6 Extended.