1. Would you be okay if I had to cancel a session if something urgent came up?
I'm not sure the tenses are quite right. Assuming you are asking in advance, for example before booking a series of sessions, I'd say 'Would you be okay if I have to cancel a session if something urgent comes up?
2. She is an MA in economics / She is MA in economics. She has an MA in Economics
3. Did you do an MBA or MA? This is fine
Student or Learner