Please make corrections.

1. Scheduled departure time for/to Africa. Are both useable?

2. I'd prefer if I called/call Jamal first. Which one is the correct way of saying it?

and

I'd prefer to call Jamal first.

3. I could probably find it if we were in downtown Chicago. Or

I can probably find it if we are in downtown Chicago.

What's the difference above? Are both useable?

Thank you!