Here’s the thing about Minions. It isn’t officially open, so it may or may not be. Then, it is located before the checkpoint for early entry eligibility, so anyone can ride it. Since it is one of the few rides for children lines build very quickly. I’ve seen 30 to 45 minute waits before official park opening before. It is also 14 minutes long compared to the Mummy and Gringotts which are only about 5 minutes long each. All this is to say you probably will not be able to fit it in and still make IOA by opening.
You have two options if you want to try for it.
Option 1) Be at the very front of the early entry crowd to get in the park. Then head to Minions very first and try for a walk on. This may or may not work depending on how early they open it. If you ride right at 8:00 without waiting, you should be ok to do Mummy and make IOA. If you miss the first group, you’ll likely have at minimum a 15 wait for the ride to cycle through before you can enter. Then another 8 minutes in the actual ride. It will be 8:30 or after by that point and doing Mummy and getting to IOA may be tight. If you are ok with getting there right at 9:00, you’ll probably be fine.
Option 2) Ride in the stationary seating section. This section is always a walk on. The line can be 2 hrs long, and you can walk straight up and ride. You’ll still need to time it right because again if you have to wait for the group in front of you to cycle through and then for you yourself to go in, you’re looking at the whole experience taking 20 to 30 minutes even for a walk on. The benefit to the stationary seating is that there’s no real advantage to riding first thing in the morning. You could do the stationary seating at anytime during your trip.
Personally, I’d ride Gringotts and do the spells two separate days. More people are catching on to doing the spells during EE. Focus on the spells during the first few minutes the park is open while others are rushing to ride. Because as the morning goes on, those same people who are rushing to ride will get off the ride and head for the spells as you were planning to do. Also, when you are done with the spells, take time to check out all the shops before they fill up with people. They are very small, and it only takes a few people for them to start to feel very crowded.
Here’s the thing about the HP sections, they stay busy all the time. You can go during the least crowded time of the year, walk the rest of the park and not pass a single person, but when you enter one of the HP areas, you’ll see people. They are definitely better during early entry, especially the first half of the hour as people trickle in. Night is kind of hit or miss. It is less crowded than earlier in the day, but that doesn’t mean not crowded or that there aren’t still lines for rides. It really depends on how crowded it was that day to begin with, how late the parks are open, and if the rain has come through and ran people off. If your options are afternoon or evening, definitely do evening.
Beginning of September hopefully won’t be too crowded. We’ve done both parks multiple times with and without EP. Yes, it is easier and more enjoyable with EP, but you can still do a lot without it. Try for the busiest attractions first and last like it seems you are already planning. Use single rider for the moderately popular rides, and enjoy the less popular rides like ET when the lines are longest for everything else. You can also take advantage of shows and long meals during the busiest parts of the day or return to your hotel for a pool break. We routinely show up with no plan and just wander around doing whatever doesn’t have a long line, and we get lots done. I don’t suggest that for first time visitors, but it just gives you an idea that you can do well without EP.
