I’m thinking that since we have free will then yes they could change their destiny...seems to me that this is the course God wanted laid out for them, but not a guarantee that they would follow it. Could be way off base here...just what came to mind first.
I think they could change their destiny but God has the Power to see what they would choose to do. He saw every decision they would make and uses those decisions to Make it how God sees fit! What an incredible God