Photo equipment for Australia Expedition?

I'm planning on traveling to Australia this summer with National Geographic as part of one of their high school expeditions and I'm looking for advice on gear. My main struggle is there's such a diverse amount of work I'd like to accomplish which requires lots of different gear and I don't want to overpack or take on too much. I want to shoot Underwater photos, Wide angle/scenery, Astrophotography, and Good photos of the animals. We're going to be going all over from snorkeling in the great barrier reef to Sydney and the zoo there to the rainforest and camping in the outback. They recommended we bring some all-inclusive style lenses aka telephoto but I value a good depth of field and don't want my photos to look like some average tourists. I've been into photography for a year and a half and have a nikon d800 with a 50mm 1.4, 90mm 2.8, and 28-300mm telephoto. Personally I enjoy portraits so I use my 50 a lot but they advised against bringing many fixed lenses as the weight builds up. Overall what are your thoughts? I've been looking into the 24-70 and 70-200 2.8 vr ii lenses but they're quite expensive and I don't want to spend all my money on the wrong gear. Also for underwater pics I'm torn between buying housing (I'm looking at meikon but they don't have any extra ports for the d800 housing so I'd be stuck with a 35mm if I buy one) or buying a low cost waterproof point and shoot. Any advice helps, thanks!

Just buy one of those zombie survival kits you'll be fine.

I'd skip the 24-70/28-70 lens. When traveling you'll either be super wide or super close. Go with a 14-24 f/2.8 and a 70-200 f/2.8. That'll cover nearly 100% of the scenes that you'll come across while on land. Plus, if you bring an underwater housing for your D800, you would want to be using an ultra-wide like the 14-24 f/2.8 anyway. Bring a fast prime like a 35mm f/1.4 for those campfire shots. I'd skip the 50mm since you already have a great portrait lens in the 70-200. You may want to bring a 1.4x or 2x teleconverter too.

Not sure what tripod you have, but you'll want to ensure that it's not too big to bring it as a carry on. The same goes for all of your other camera bags. NEVER check them in! Always bring them with you as carry-on luggage.

I don't have any experience with underwater shots, but I would highly suggest that you figure out just what kind of opportunities you'll have for UW photos. Going to some river or unknown lake may call for a water-proof plastic bag or just a point and shoot. But the Great Coral Reef, is whole other animal where I'd want to use my DSLR or a Sony A7R II in a underwater case.

For macro, you could reduce the weight of your kit by leaving the 90mm behind and just taking an extension tube. Using an ET on the 70-200 will likely afford you the close-up capabilities that you need.