Regarding the interview process, my information packet from Emirates states that applicants must provide their own transportion from the hotel to the interview site. What's the best way? Taxi? How much local currency will we need?

Taxis are relatively cheap. Five dollars will get you just about anywhere and taxis everywhere. Five dollars is a bit less than 20dhs. Where the hotel is to the interview building will cost very little. Don't stress about that part.