1.Do you have any idea whether you will be available on January 2nd?
2.Will you be able to know if you will be available on January 2nd?
3.Could you tell me if you will be available on January 2nd?
4.Is it possible for you to know if you will be available on January 2nd?
5.I wonder if you will have any time off on January 2nd.
(一楼二楼的回答在语法上都有一些小错,外国人一般不这么说话,