Glac13:
So now that I've managed to put the fear of God in you, let me give you a few hints that might help (hopefully) to put your mind a bit more at ease:
1. Stick to the dive guide like glue - in fact, tell him/her that you plan to do that beforehand, maybe a few feet above or next to him or her. It is somewhat reassuring to have someone who knows what the heck is going on, and to have him/her nearby in case you need him/her. That should help reduce the level of anxiety and maybe save you a few hundred pounds of air.
2. If the dive plan for the pass dive is to occasionally stop and stay in one place for a while to look at stuff passing by, hide behind a rock or a coral formation to shelter yourself from the current - don't hover above the bottom because again, it means that you will have to kick to stay in place - and kicking eats up air. Of course, don't trash the coral either.
3. Remember the fundamentals - inhale slowly and deeply: drag that inhalation out for as long as you can (think of a junkie smoking a joint) and then exhale slowly. Try to think about this (the breathing part, not the junkie!!) every so often - you may catch yourself breathing shallow and short, especially when excited or tired. If so, settle down and work on your breathing.
4. If you do the pass dives, it may be comforting to you to know that these dives are normally done with the incoming tide, very seldom with the outgoing tide. That means that even in the remote event that you are separated from the group, at worst, you will wind up in the lagoon, inside the atoll, and not on the express to Japan.
5. Make sure to bring a safety sausage. If you are on the surface by yourself, it will help the boat find you and it will make you more visible to other approaching boats. There isn't heavy boat traffic in the lagoon, but nonetheless, once you surface, always be alert for boats. If you've never deployed a safety sausage from your 15 ft. safety stop, I suggest that you don't. Just wait til you get to the surface. I know of one person who attempted to deploy it from his safety stop. He hung on to it, got yanked up to the surface, and got bent.
6. Once you've surfaced, it is also best to turn sharply left or right to get out of the path of the current. Then just pump up your BC and relax. It tends to be calmer and the current will eventually die down once inside the lagoon and away from the mouth of the pass.
You've picked a great destination for a honeymoon and diving. The Tuamotos have some of the bluest and clearest waters I have ever seen, along with Micronesia (Yap and Palau). I've only been there in January and April, so I don't know how the waters will be in July, but just for the heck of it, if the water is nice and clear, as you move along in the water, you ought to be able to see that there is hardly a particle in the water. Record that mental image in your mind, because it will serve as the standard by which you gage the clarity of waters you will see in future destinations.