Decided to revamp their designs and bios. Ashes was meant to be a foil to Dust and vice-versa, but I don't think the original designs conveyed that as well. 

Summary:

Dust the Coyote (left) and Ashes the Wolf (right). Named after the phrase "ashes to ashes, dust to dust," Dust and Ashes are non-identical twins with friction-based powers. Dust's fur is prone to building up immense amounts of static electricity as a result of friction, while Ashes' fur is prone to building up immense amounts of heat as a result of friction. Through this, Dust can use lightning and Ashes can use fire. 

As for how these powers tie-in to their names, Dust's static electricity attracts dust onto his fur, which he can use to create dust clouds. Ashes' bursts of fire often create a thick black smoke (i.e. airborne ash).