I'm not in your position so I wouldn't want to give advice. I guess there's some questions to ask the medicos. How is the tumour in the breast likely to change in the future and is there any value in removing the lymph node? The node surgery is the one that causes most grief afterwards as the nerves are often compromised which is not pleasant, and there is a small chance of lymphoedema. I wouldn't necessarily brush of cording, either. For some of us (pointing to myself), it is not resolved by physio, merely managed, so while not by any means a deal-breaker, it shouldn't be dismissed as irrelevant. Is a short break from the medication likely to cause any problem? On the other hand, I'm sure that you would love to get rid of that tumour and it sounds like it's going to be a very minor operation. There would also be benefit in having definite pathology of the cancer.
If it were me, I would ask more questions about the need for the node removal (and you may already have) and I would also question the impact of going off meds (again, you may already have).
It sounds like you have had a really positive result from the medication which is great!