1. Congratulations, your addiction seem to be progressing at a slow rate. hehehh
2. Regarding the oncidium: Remove that leaf and keep an eye on the plant. Should be ok if it is just heat damage. It will take some time to recover though.
3. The rhizome on the cattleya will need to be planted below the bark level, though it will not hurt to let it be above the bark. Cattleyas can grow in bark or mounted, so either way it is fine. My preference is when potted that the 'root' system is below the bark line in the pot. Again, JMHO
4. The phal seems to be in shock. Phals do not want to stay wet, but do need moisture all the time since they do not have p-bulbs to store water. Most likely you are letting it dry out too much. (That or you may have damaged the roots when repotting.) Either way, it should be fine with time. Orchids for the most part are pretty tough.