Some crabapple cultivars have peeling or exfoliating bark and there is nothing to worry about. In other cases, peeling bark is environmental, caused by southwestern exposure or sudden hard freezes. There's little you can do about it, unfortunately, except pray to the weather gods.

The white stuff in your third photo is blurry but most likely is an insect pest called wooly apple aphid. There are a variety of products you can apply to reduce the incidence. They range from least to most toxic. One of the least toxic is horticultural oil which is applied in the dormant season (when other desirable pollinators aren't around) to smother the overwintering aphids. Systemic insecticides with imidacloprid as the active ingredient also will be effective against wooly apple aphids but they potentially will kill the 'good' bugs, too (ie. the bees and other pollinators who feast on the crabapple blossoms) so should be used only with great thought. Here is a fact sheet from CSU Extension that explains your options in detail: 

http://extension.colostate.edu/topic-areas/insects/aphids-on-shade-trees-and-ornamentals-5-511/