You probably burnt the leaves right off your tree with your home brew, especially if you used it multiple times and in the sun. Hydrogen peroxide is a bleaching agent (remember peroxide blonds) and dish soap usually contains a degreaser so takes the waxy coating off the leaf surface. Both bad ideas for bug killing as the plant usually dies too.
The white crawlies in the soil are not mealybugs as mealies don't move fast enough for you to notice they did. They may have been fungus gnats or the nymph of some other insect.
The repotting added another layer of stress to any already stressed plant. Take good care of it and it will hopefully recover. New leaves in spring.
