Let me add to what 'trds' wrote. Your posting clearly states that the argument is based on human logic. What logic do you use? What are its axioms? Please list them.
When you list them, please tell us, is the logic you use perfect? The logic determines the validity of the conclusion, especially when we try to make something that is not given in th scriptures to be scriptural. The scriptures being the revelation of the will and mind of God. From this stand point, the knowledge about the limitation of the human logic is highly desirable for us to understand the possibility of being wrong in our conclussions.
You should also consider the following: Is there any verse in the Bible that tell us that God created Satan? In Isaiah 45:7, which you quoted, the Hebrew word for "evil" is RA, which is also used at many placed. Genesis 2:9, 17; 3:5, 22 are four of them. The "evil" (RA) in Isaiah 45:7 is different from Satan (HASATAN = Accuser) as se read in Job 1:6, 7, 8, 12, 2:1, 2, 3, 6, 7, and so on. It is also different from Devil (SAIR = Hairy one) in Lev. 17:7 and 2 Chr.11:5, or (SHED = Spoiler) in Deut. 32:17 and Ps. 106:37).
Therefore, we have to consider the logic that is used to come to the conclusion, as you stated in your initial posting. Please tell us about it.