Let me try and answer your questions.
1. If you feel cold air, but it isn't below 50 degrees, then it shouldn't be a problem. Regarding light - just because a plant has enough light to grow a leaf, it may not be getting enough light to actually bloom. 9 out of 10 times, lack of light is what keeps a mature orchid from blooming.
2. Get a tray. Put the rocks in the tray and fill with water to the top of the rocks. Then set the orchids close together on the rocks. No water should go into the pots.
3. Maybe this phal needs to cool down to get it to spike again. Some do. Move it closer to your window where you get the cool air (as long as the plant doesn't get below 50 degrees - it will be fine.)