Will UofT and Waterloo revoke my offer if I only complete 3 A-Levels instead of 4?

Hi everyone, I’m an international student (A-Level curriculum) and I’ve received conditional offers from UTSC stats, while Waterloo Honors Mathematics is under review . When I applied, I listed 4 A-Level subjects (Mathematics, Further Mathematics, Economics, and Physics). However, I’ve already completed my Math A-Level with an A* grade, and I’m currently predicted A* in Further Math and A in Economics and Physics. The problem is Physics. I’m really struggling with the workload and I honestly don't want to sit the exam or continue with the course (especially the repetitive memorization parts). My concerns 👇

1. My UofT offer says "Maintain your current academic standing" but also mentions I must present "at least three different Advanced Level subjects." If I only submit Math, Further Math, and Econ, am I safe?
2. Waterloo’s requirement for Math is usually AAA. If I drop Physics but get A*ABin the other three, does that violate the "minimum final grade" requirement?
3. My school counselor is being strict and says I must take all 4 because I applied with 4. Has anyone here dropped a 4th A-Level after getting their conditional offer? Did you have to email the admissions office first, or did you just submit the 3 results in August? Any advice would be greatly appreciated. Thanks!