We used Fastpass for EE twice in the same day on the last trip. We went straight to EE at opening and picked up the FP, then we headed to the Safari and rode that after waiting only 15-20 minutes in the standby line.
Then later we used out EE fastpass, and after getting off the ride, deceided that it was so great that we HAD to ride again. So we picked up a second FP right after riding and used it again later in the day!
It is a great ride! Enjoy!