Hello Susan, I hope you're feeling ok! I was very lost when I first got the information. Definitely information overload for me but trust that you're in good care and if you're ever lost just ask.
I've just done a double masectomy and your daughter is very funny with that tee! Haha. But if you're getting it in that print I would suggest a button down version. You will have one or two drain bags after surgery, I found it helpful to have pockets. Either in the shirt or pants with huge pockets. The breast care nurse will take care of you too, I don't think you have to reach out, they will be at the hospital.
All the best for your treatment!