F1 Visa - Admission Date

Currently I am in USA in F2. I am applying for F1 Visa for the first time and with great difficulties I got a consular emergency appointment in Mexico and it is 40 days before my I20 mentioned earliest admission date and I don’t want to miss this appointment as it is closed everywhere in India. Below are my questions, it will be great if someone can help me in answering the below questions.

  1. Do you think, am I allowed to enter before earliest admission date which is mentioned in I-20.
  2. Do they cancel F2 Visa status in the passport while issuing new F1. If they are not cancelling the previous visa - F2, I can use the F2 visa to enter and on later date again I will go out of USA and enter with F1. Is it an option?