Greetings, dear Corpus, and peace to you! I would like to respond, if I may. Thank you! Here is what I received from my Lord:
a) In that moment, if Judas, through an excercise of free will, had chosen not to betray Jesus, would it have been necessary for Jehovah to have caused another close associate to commit the betrayal?
The Most Holy One of Israel did not cause Judas to betray my Lord. The prophecy never said WHO it was that would fulfill the act, but simply that the act would occur. Even my Lord didn't know it would be Judas. It was Judas who began to reveal that it would be him through his words and acts. The Most Holy One of Israel knew that ONE of those close to my Lord would betray him, one who shared his bread with him. If it hadn't turned out to be Judas, it would have turned out to be one of the others.
Did free will come into play in that decision at all?
Yes, it did. Judas could, at ANY time, have resisted the Adversary. He didn't. Had he done so, the Adversary would have simply moved on to another disciple... and another... and another... until he found one who allowed himself to be used. Given the rivalry/jealousy between and conduct of some of them, it really wouldn't have been that hard to find a willing "vessel." Keep in mind, Peter himself was on the brink ("Get behind me, Satan!" was said because Peter was allowing himself to be used to try and talk my Lord out of doing what he came to do). And probably was many times (he literally denied that he knew my Lord!). But apparently he wasn't the easiest target... or most predictable (the Adversary was on a mission and couldn't risk having it thwarted because the "vessel" was wishy-washy).
and b) if the betrayal of Judas was prophesied, foretold, pre-decided, did he commit an unforgivable sin by being the instrument of that prophetic fulfilment?
First, again, betrayal by JUDAS was not prophesied, foretold, OR pre-decided. That is a LIE and a false teaching. It was simply fore-KNOWN, so that it could be FORETOLD... that my Lord would BE betrayed by one close to him... which is not the same thing. The Most Holy One of Israel can state, with certainty, what WILL occur... because, within HIS timeframe, it has ALREADY occurred. Our FUTURE... is HIS PAST. An example would be ant, in comparison to us. We can see an ant travelling and state, with some certainty, what the end result of his journey will be. How? Because we can see its path... including any "obstacles" that exist. We can see that it "might" go this way... or "must" go that way. The ant, however, can't see that far ahead. Now, we can try to assist the ant by trying to help it "detour" to avoid the obstacle... but if it insists on staying its course... it will eventually reach the obstacle. We can also see its death... if it's by, say, a shoe or spray of Raid. Again, we can try to help it deviate so as to avoid what's coming, but if it insists on staying the path... or if the shoe/Raid follows IT, it will die. We can SEE this... because our vision... and lifespan... far outdistances that of an ant.
It is the same with the Most Holy One of Israel. Because HIS timeline is not limited to ours... He can see our "path"... individually and as a species... so as to know "what will come to be".
Second, to say that Judas' sin was "unforgivable" is premature... and judgmental. Judas repented (which is why he tried to hang himself); however, it is not ours to say that such is insufficient. Nor is it ours to say that his sin can't/won't be forgiven. And it is absolutely FALSE to say he won't be resurrected. Both he and Adham/Eve WILL be resurrected; however, whether it is to life... or to judgment... is unknown. Because the Most Holy One of Israel shows mercy to whomever HE wishes to show it. My Lord is recorded to have said, however:
"There will be resurrection... of the righteous... AND the UNrighteous: the righteous to LIFE... the UNrigtheous to judgment."
Neither Judas, Adham, nor Eve, therefore, have been judged. They must be resurrected, however, for that to occur. As a result, none of them have had their "nakedness" (sins) revealed before ALL... nor a determination as to whether their names are written in the Lamb's Book so as to have their sins blotted out. Mankind has to wait and see.
I hope this helps and, again, I bid you peace!
A slave of Christ,
SA