If the interview letter says to check in at 10:45, then it is best to follow the instructions to the teeth. You don't want your application to be shelved because of a technicality like that. Besides, you might have to write your essay before the interview which might explain the earlier arrival time. I can just imagine some of the ADCOM people saying, "Sorry, if you can't follow simple instructions, how are you going to survive rotations when your attending and preceptors are barking instructions at you?"
Some general questions you can think about and this may apply to almost all pharmacy interviews:
1. Why pharmacy?
2. Why pharmacy and not nursing, medicine, or dentistry?
3. What are your strengths and weaknesses?
4. If person X refuses to do his share of the group work, how would you handle the situation?
5. What are some of your hobbies?
6. Where do you see yourself in the future? short term vs. longterm?
7. It's busy at your pharmacy and you get a phone call from a prescriber demanding that you dispense the medications he ordered although you know he is notorious for overprescribing or making errors. How would you handle the situation?
8. What have you done to prepare for your future career?
9. How can you contribute to your class and ultimately your profession?
10. How would you juggle a demanding profession and a personal life? What sort of sacrifices are you willing to make? unwilling to make?
If the interviewers did their homework, they will actually point out that you do indeed lack experience in pharmacy, but however you can do a 180 and show them how you can compensate with your community service and extracurrics during school. Just show them that you are a genuine person who cares about people--your classmates, family, neighbors, etc--that want to be at UCSF to make a difference. Good luck all!