Hi Junebug, I see a couple of problems.

If your tank is glass bottomed, you may have put too much weight into your tank. The bottom may eventually crack under the weight of all the rocks, plus wet soil plus plants. You didn't need such thick layers of stuff under the soil. A much lighter drainage solution is to cut a piece of plastic ceiling light screen to fit the bottom, and over it place a piece of water-permeable landscape fabric. Over this you can put the soil mix.

Jewel orchids don't really grow in soil. They grow in loose leaf litter lying on top of the soil. Their thread-like roots are easy to suffocate with soil. A lot of gesneriads are like this, too. They need very high humidity and just barely damp medium. In a well-sealed terrarium they might only need watering a few times a year. They crawl over and send their roots into the loose material. Sphagnum moss also works well. The plants might do better if you lay them sideways, and just barely cover the roots with moss. The stems will root and the plants will grow horizontally.

It's an aquarium, so it definitely won't break. It's designed to hold while full of water.

The jewels are in a very well-draining mix I made, not straight potting soil. At the top it's equal parts lava rock, moss, and soil. I'm going to be adding more bark as well.

Additionally they are laying sideways with their roots just under a layer of damp potting mix. I honestly don't think there's anything that will help them at this point though, they were in such bad shape on arrival.

I do have a picture of them today. They are much worse, with a few exceptions. (don't mind the random orchids in their growers pots lol they arrived before their permanent houses did)

https://i.imgur.com/MbO1UpA.jpg

Don't necessarily call the jewels out... they are capable of sprouting new leaves and propagate from a stem (unlike most orchids)... if the whole thing composts itself, then RIP, but don't be hasty, you may be pleasantly surprised though it may take awhile.

I checked on them this morning and most of them actually look a little better. Feeling hopeful ;)

There is one that turned black and melted into goo. Don't think that one's going to be returning, but some of the others look okay this morning. I wasn't going to pull them unless they died, so they are all still in there.

The one that I tossed in the gecko cage is actually looking better too, and firmed up quite a bit. It's not even planted in an acceptable potting mix LOL.

Well either way, the tank is coming along. I mounted the angraecum last night and will be doing a little work on it tonight as well to get it better situated. The rest of the plants should be arriving soon.