Questions about my new orchids

[wiacomm]

Hello all,
I just bought a dendrobium noid. The medium was broken down badly so I removed it all and then just sat the plant on top of some lava rock and bark, held up so its not resting on the medium. The leaves on the bottom, like 6 leaves had all turned yellow and leathery. Will that harm it or should I plant it in the medium?

I also bought a noid oncidium, it has yellow flowers on it. When I got it home I realize it is actually only 1 that is planted in dirt with perlite. And 2 others that were just sitting on top of the dirt! I know that this plant doesnt want to be in dirt right?
I took the 2 that were sitting on top and put one in my regular medium of lava rock adn bark. The other one I put in a jar half full of medium and planted the part that is a dead root looking thing (very large about 6 inches long with nothing on it) and the other part with the pbulbs is above the medium. Lots of roots hanging out and healthy looking even if the bulbs are shriveled looking.
The ones that were sitting on top of the soil are pretty shriveled up so I watered them a lot. The one in the dirt seems to be pretty healthy. I didnt remove that one from the dirt as i am afraid to damage it.
Has anyone seen this done with oncidium before? Being put in dirt? Should I remove it now and put in medium? The nursery I bought all my plants from is well established and I havent had issues before but the last 3 plants I have gotten there are all sick or have some sort of issues. NO more from there for sure.
I would like to save these two plants if at all possible. Please help if you can.
Best Regards
Cindy

pic 3 is the phal that I got from same place. The leave that had the yellow stripe is now all yellow and leathery. I had to cut the spike off as the buds all blasted.