When plants are stressed, they are magnets for insects and disease. Below is a link that is pretty comprehensive for disease problems.
First, take a good look at the leaves of the plant top and bottom. When they are weak, mites, mealy bugs, white fly just find them. Try to hose or wipe off the leaves once a week if you can to clean them of dust and critters. It is best to do this outside, but if that is not possible a deep sink or tub will work.
The stems and roots of the plants should not be black and soft.
When the leaves grow back they should be medium green and not soft. If they are dark green and soft they need more light, put the light source closer for 14-16 hours a day. They need to have a rest period from the light. Turn your plant so it does not lean toward the light.
It is hard to get enough air circulation in a house, and the plants need less water because, they are growing less actively and there is no sun, wind or air to evaporate the water off the soil. (That is why a fan helps). If the soil stays wet for a prolonged time, then soil molds and fungus can grow on the soil surface. It does not always hurt the plant directly. It is a sign that the pot is staying too wet for too long.
If your white bugs on the soil don't move they are probably some type of fungus or mold. Like tiny mushrooms on the soil. They can be broken up by using a fork to loosen and break up the soil. If the root ball is compacted, re pot and watch the watering. Water the plant in the sink. Try to dry it on a rack before putting it back in place. Avoid using saucers if you can because they keep the pots wet.
A lot of the time it is just finding the right place to keep the plant. Sometimes a rack is better than a saucer in the living room. A shop light or under cabinet light suspended over the plant about 8-10 inches for 10-14 hours works better than indirect light from a window from one side. A fan to circulate air around the plants would simulate natural breezes.
Happy gardening in Hawaii. Gardens are where people grow.