Your photos from your other post showed sunburn on the Peace Lily. Move it away from the windows. You could put it on a table, or even on the floor across the room, where it doesn't get direct light. Maybe even into another room, with less windows. They really do well in very low light! Once it recovers, and has dark green leaves again, you can try giving it a bit more sun to help it to flower.
This site recommends placing the Peace Lily 6 to 8 feet away from a window. It also says that they have been known to grow fine in rooms with no windows at all, using only a plant light.
Your hypoestes, or "Polka Dot" should be fine near your Eastern window. But, you may find that the new leaves are less vibrant, or grow in solid green if they aren't getting enough sun. http://www.guide-to-houseplants.com/polka-dot-plant.html
Gardenias prefer indirect light (preferably near a southern) window where they receive sun for at least half of the day. So, I wouldn't worry about your gardenia getting too much sun near your eastern windows. http://garden.lovetoknow.com/wiki/Gardenia_Indoor_Care