The axes of draconic alignment are not good/evil and order/chaos. Draconic alignment fluctuates between sated/hungry and asleep/awake.

Scale color and resistances are sympathetic reactions to their environment, not species-level traits. A dragon with a volcanic lair that moves to an arctic ice cavern will change from red to white the next time she molts (which could be months or years; the specifics of draconic lifecycles are still poorly understood, and individual dragons have some degree of conscious control over the process).