Answer: It sounds as though there are several things going on with your citrus trees but I think they can all be corrected. First of all, when you move a tree indoors after they've spent the summer outdoors, they will go through a stressful adjustment period. Light levels are lower indoors and temperatures and humidity are different, too. Leaf drop is normal during adjustment periods. What you can do to help is to provide as much bright light as possible, water often enough to keep the soil moist but not soggy wet, and mist the leaves daily to compensate for the dry indoor air. You'll also want to make sure your trees are not in a draft or near a heat register.
The fuzzy things you see are probably mealy bugs or cottony scales. Either can be controlled by dabbing with a cotton swab dipped in alcohol. This will dry out their crusty outer shells and essentially kill them off. The Insecticidal Soap you used can be effective against these pests because the fatty acids will either coat them enough to suffocate them, or will break down their outer shells and they will die. I find that while dabbing each pest is labor intensive, it is also quite effective.
Citrus trees need a regular source of water while they are developing fruit - a wet period followed by a dry one will cause the fruit to drop. Plant immaturity and lack of pollination will also cause the fruit to abort.
Hope this information helps you understand what your trees are going through. Just keep them well watered and warm and they should replace the dropped leaves and may even flower and set fruit while indoors.
Best wishes with your trees!
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