The angels still had free will AFTER the original sin was committed.
Sorry if I was not clear but free-will about changing the choice between good and bad. The most important feature of free-will. They can't change their mind between good and bad but of course they have will about things in their main choice.
God didn't have the foresight with regard to their eating from the tree of the knowledge of good & evil but he did in the case of the tree of life.
Having the foresight to realize what would happen if Adam and Eve remained in the Garden of Eden, God takes the precaution of putting a barrier between them and the Tree of Life.
God being omniscient proactively took steps to ban Adam & Eve from the garden of Eden after they sinned as he foreknew that they would eat from the tree of life and live.
Yet he didn't foreknow that they would eat from the tree with the forbidden fruit and thereby take steps to put the tree with the forbidden fruit out of their reach - only the tree of life was deserving of such a proactive action.
Or is it that God is not omniscient - not even of high intelligence - because he did not realize that without a moral sense, Eve and Adam would probably eat the fruit sooner or later? Any parent who puts a plate of cookies in front of their toddler and tells them not to eat any is aware of what the infant will do.
Please read about molinism.
So God took away their free will because they rebelled?
No. Because they were exposed to a total revelation. Angels lost the free-will too.
do have free will in this instance - I decided that the ton of gold was worth far far more than the pin and therefore chose the ton of gold instead of the pin.
Nobody mentally sane would choose the pin. There's no freedom in this choice.