You could try to just humidify the area right around your plants, and keep the rest of the room dry. To do this, stand your plants on trays (old cookie sheets work great) of pebbles and keep the trays filled with water. The bottom of the pots should not touch the water. (the pebbles hold the pots up)
Just run the humidifier on especially cold and dry days when the heat in the house is on to circulate the air, and keep it near the plants and the window. (assuming your plants are near the window) I also hang damp towels around my plants in cold weather when I bring them into the house. A damp t-shirt or two on clothes hangers would work, too. Just don't let them drip on carpet, or the carpet will get moldy.
But if there was a plumbing leak that caused the damage, it also probably caused your moldy bedding and all that stuff as well. You weren't helping the situation with the humidifier, but all by itself, you couldn't possibly cause that kind of damage with a humidifier.
