Ethicality of continuing my Ph.D. with intentions of leaving I am currently in my first year at a funded Ph.D. program. I have a graduate teaching assistantship in the form of teaching three introductory biology labs (1 credit per) plus the other responsibilities of being an instructor. I also have a six credit (tuition waiver) course load and a stipend. 

Prior to coming to this program, I declined an offer from another funded program. It was due to financial reasons such as making a big move to the city and whatnot. I was a fresh undergraduate out of college and I was not ready for that move. I am in the position to make this move now and the offer is much better than my current program. 

I have many different quarrels with this current program. There is a lack of structure and much of what I expected at a Ph.D. level course/program was not met.  I dislike the current field I am in and I don’t believe I would be happy doing this for the next 4 years. I did not have intentions of leaving prior to starting here, but as I mentioned things here are not as what I expected. Through discussion with the head of the department I declined, I was able to get my declined admission deferred to next fall. In February, I will hear if I receive funding again.

Now my issue is that I am currently in a lab rotation with my prospective advisor and I have not told anyone that I will be leaving. I am afraid that if I tell anyone that I plan to leave after the year, I will be looked down upon and it would affect my courses for the year. I want to withdraw from the lab rotation because the program I will be going to does not have any use for such a course. However, I am worried that if I tell my advisor why I am withdrawing, it will impact me negatively. In the off chance I do not receive funding, I will most likely be staying in this program and if they know I wanted to leave and didn’t because of funding, I fear I will be looked down upon. 


How unethical is it to continue this year and finish up without mentioning any of my intentions to leave the program for another? 
If I do withdraw from the lab rotation, should I mention why I am doing so or just mention that I was not expecting the course work to be so intense (which is true due to my teaching taking up so much time, I am behind). 
How unethical is it to use my 6 credit tuition waiver to take courses in the spring that would hopefully transfer to my other program?


My contract runs 9 months so I can’t just leave.
How unethical is it to continue this year and finish up without
  mentioning any of my intentions to leave the program for another?


It is not at all unethical to continue until you know for certain. I see this as a situation where you are considering your options. You would LIKE to leave, but you are also considering staying if you have no funding at the second program. I certainly don't think you have any obligation to mention your decision until you hear about funding. In February, your current program will still have the opportunity to give away your funding to a new student/another student, so you are not harming anyone by waiting to speak up.


  If I do withdraw from the lab rotation, should I mention why I am
  doing so or just mention that I was not expecting the course work to
  be so intense (which is true due to my teaching taking up so much
  time, I am behind).


I don't think you should withdraw. If you stay, this would be your advisor. And if you don't get funding, you may stay. So you should make sure you have a good backup plan with this advisor at your current school.


  How unethical is it to use my 6 credit tuition waiver to take courses
  in the spring that would hopefully transfer to my other program?


You will likely need to decide on spring courses before you decide if you should stay. If possible, choose courses that would prepare you for either path. If not possible, I don't see a problem with using the waiver you have earned through your teaching in a way that would be of most use to you.