In hebrew, there is a special verb, bara, that means to create out of nothing. It is reserved only for God. This verb is used in Genesis, God created the Heavens and the Earth. Everything came from that source. After that, you can fashion, mold, make -- there are many verbs that can be used to build/shape that don't involve ex-nihilo creation. So Isaiah 45.7 follows the same verbal pattern as the creation account in Genesis.
In both, the verb 'bara' refers to the creation of darkness and evil. That God created it out of nothing. However the verbs ytsr, and 'sh, meaning to shape and make are used for light and peace. This suggests that the light and peace are secondary or higher level creations built from the raw stuff of darkness and evil.
Note that 'evil' here, ( r') has a broader semantic range than in English. It could also mean disorder, calamity, etc.
This idea of darkness preceeding light and evil preceeding peace is echoed in other parts of the Bible. E.g. in the Genesis account, God created the Heavens and the Earth, but there was darkness. Then God said "Let there be light". The light shines out of the darkness just as peace breaks out of evil.
Also notice that the parallel of evil is peace, not good. God sees the light and says it is good, so good is an attribute of light as well as of the higher order creations, but the end, the purpose of evil is to bring forth peace, or reconciliation, just as the purpose of darkness is to be a backdrop in which light can be brought forth. Both of these higher order creations are "good".
This is similar to other processes of molding or fashioning. E.g. God takes some impure lump of rock and puts it into the fire and the result is pure gold, or a pure thing. That pure gold is "good". The impure thing is the basic stuff out of which the good thing comes. The basic stuff is created ex-nihilo, the good stuff is fashioned/made. This is the divine hierarchy.