Our experience last week was that the monorail went out the first time 10 to 15 minutes after park opening. Using it to try for the front of the Nemo line was useless. We were in line for the monorail on Wednesday morning and got the first one out. By the time we hit the park, the line for Nemo was already 1 1/2 hours long.
If taking the monorail for early entry, it's probably the same. I'm afraid to say that on early entry days we were a little late getting around so 30 minutes of the EE had already passed by the time we got in line for the monorail. If you're staying at a resort hotel, pay particular attention on EE days. There will be a line of people who won't be using EE, waiting for the monorail at park opening time. You need to go toward the front where they're checking bags and show the proper paperwork. It's marked, but you can be deceived by the line.
Have fun!