Okay...here's what I think is going on with the Miltassia. I think the plant was shocked somehow in shipment...probably due to temperature fluctuations. I think the plant is just now showing the damage that occurred when it was sent. It can take a little bit for plants to show damage sometimes...I have a Cattleya that I accidentally let sit in too-hot sun weeks ago, and it just lost a pseudobulb yesterday. The leaves turned yellow and looked very much like yours (except without all the spots). At any rate, I don't think you caused this.
You will most likely lose the bulbs with the worst-looking leaves. You don't need to proactively remove anything, though, as you don't want to traumatize the plant further. But the good news is that the plant seems to still have several bulbs that are quite green and decent-looking, so I think you'll only end up losing some of the plant.
Here's what you can do to help the plant bounce back:
Keep it out of bright sunlight for now; it won't be able to tolerate full Catt sun until it recovers. Right now it needs to spend its energy rebuilding any cells it can. Make sure it has plenty of humidity, and give it some Superthrive if you have it. Leave it in the mix and pot you've put it in, but baby it until it recovers from whatever traumatized it. Be prepared for some leaves to fall off, and perhaps some bulbs to shrivel or flop over. If that happens, you can usually just give a little tug and the dead bulb will just pop right off. You shouldn't need to perform any "major surgery" though.
Once the plant has finished dropping anything that didn't make it, just keep an eye on it, and then you can gradually transition it back to full light levels when you begin to see new growth.
I think this one will recover on its own as long as you keep it out of really bright light and make sure it gets enough humidity, but it's definitely suffered a major setback. With tender loving care it will hopefully start putting out some new growth within a month or so. That's when I'd start moving it back to regular light levels.
As for the second plant, ID'ing that one is going to be really tricky without a bloom. It looks like it could be a mini Cattleya, but that's just a guess. It could also be some obscure species plant.
I'm not a huge fan of growing things on mounts, so personally I'd divide that sucker and pot up the divisions in very coarse bark in clay pots. I find that orchids that like to grow mounted often do extremely well in very coarse bark that's just sort of loosely tossed in a pot. I make sure to let the roots sort of ramble in and out of the bark, leaving some exposed to the air, so that it simulates the feel of a mount for the plant. It looks like you could get a couple of decent divisions out of that huge plant!
Just make sure you have at least three older p-bulbs included in each division to give the plant some energy/water reserves, and I think it will transition nicely to pots. I can't wait to see it bloom!
Good luck! Let us know how it goes!