Yes, I saw BD's quote in 4665, including this line:
Fanatics torture this word evil, as if God were the author of evil, that is, of sin; but it is very obvious how ridiculously they abuse this passage of the Prophet.
I took this to mean that Calvin did not believe that God is the author of evil.
As I understand Calvin here [from your quote of Calvin], he is saying that God uses an evil ruler to punish his evil subjects, but God does not create either evil. In other words, God uses evil which he does not create for a good purpose--to eradicate evil. Is that your understanding of what Calvin is saying?
Yes, that makes perfect sense to me. God is in full control. God has power over and above all evil deeds, that He may prevent some from happening, or allow some to happen for His own purposes, His good, pleasing and perfect will. And God is blameless from judgment on evil, He does not create it, He is not the author. He uses the evil that comes from man.
That is the clearest statement of the Calvinist position on this subject I have seen so far on this thread.
Now, I have this question for you. A certain Christian confession uses the following words in its worship service, which seem to me quite relevant as we approach Easter. The words are "trampling down death by death." In other words, God uses the evil he does not create to defeat and overcome the evil he does not create. In other words, the death of Christ on the cross results in the overcoming of death and the resurrection of Christ. Is that consistent with your understanding of God's will?