Board Thread:Speculation House/@comment-112.201.160.193-20160124193206/@comment-26397825-20160201084500

The Maidens have access to all the elements, otherwise Amber wouldn't have been able to use all of the Elements in her fight against Cinder, Mercury and Emerald. It is likely that each Maiden just has one element that is easier to use than the others, similar to how a ninja in the Naruto world can learn a Jutsu from any element but they have one element they learn to use easier because of their chakra affinity.

Cinder is still half Fall-Maiden. She also uses Fire Dust infused in her clothing quite a bit. Fire is not just limited to the Summer Maiden.