I believe that God indeed orchestrates what is going to happen but not necessarily with a specific person. God ordered Elijah to anoint King Jehu as King but refused and then later God had Elisha fulfill it. There's several examples in the Bible like this.
Had Jonah not repented there's nothing that states God would have still made Jonah do it or just pick someone else.
Right. God can always find someone else who will do His work if the first doesn't.
Esther 4:14 For if you remain silent at this time, relief and deliverance for the Jews will arise from another place, but you and your father’s family will perish. And who knows but that you have come to your royal position for such a time as this?”