I like the idea of Olorin being a messenger of the Valar (not Ulmo) to deliver Fingolfin's premonition. He would most likely appear in a dream.
And prophetic messages should work on multiple levels - literal and immediate vs figurative and big picture. The message St. Francis received while praying in front of the crucifix at San Damiano was, 'Francis, rebuild my church, which as you can see is falling into ruin.' Naturally, Francis took this quite literally - he was praying in a tiny abandoned chapel that was indeed in need of repairs. So, he took some of his father's belongings, sold them, and purchased building supplies to do the repairs. Francis fixed up the little chapel, just like he'd been told to do. His father wasn't thrilled about the stolen goods, though, so it led to a bit of a bru-ha-ha where Francis publicly disowned his father and was taken in by the Church. And then he founded the Friars Minor and the Poor Clares and did a lot to restore the integrity of the Church in his day.
But back to prophecy - the dual meaning of the word 'church' is integral to that story. It means both a building, and a community of believers. You can rebuild either, but in different ways.
Whatever message Fingolfin receives needs to be open to interpretation, and preferably would work on multiple levels. Fingolfin can't be wrong, and the Valar can't be liars.
So, to begin with 'Morgoth is not unassailable.' This is a true statement. Morgoth will be defeated in the War of Wrath. And even in the duel with Fingolfin, Morgoth will be permanently injured. The statement itself doesn't command a course of action or make any promises. . .but there is a strongly implied indication to act there.
'The Siege will not contain Morgoth' is another true statement of prophecy. The Siege will be broken imminently. We aren't going to be let down by this warning - there is immediate pay out. It gives urgency to Fingolfin's desire to act.
Another element of the message should be that 'True hope lies in the West'. This obviously parallels Ulmo's message to Turgon, but also is one of those unrefutably true statements. Is it a promise of aid? Not...really. But if there is any indication of when that aid will arrive, it cannot be a cheat. Eärendil is Fingolfin's great-grandson. But if this were pointed to Eärendil, it would involve Ulmo. So, rather, I think it should come across as a warning that the Noldor are on their own. If someone says they will not help you until the stars fall from the sky, you don't look up the timing of the next meteor shower...you assume they aren't helping. So if it sounds like a refusal to help, but actually reveals the conditions under which they would help...that might work. Something like, 'The Valar will not aid you while the sundering seas divide you and them.' Fingolfin could think that his suicide mission puts him on the correct side of the Sea to plead his people's case, in a 'if you strike me down...' way.
And prophetic messages should work on multiple levels - literal and immediate vs figurative and big picture. The message St. Francis received while praying in front of the crucifix at San Damiano was, 'Francis, rebuild my church, which as you can see is falling into ruin.' Naturally, Francis took this quite literally - he was praying in a tiny abandoned chapel that was indeed in need of repairs. So, he took some of his father's belongings, sold them, and purchased building supplies to do the repairs. Francis fixed up the little chapel, just like he'd been told to do. His father wasn't thrilled about the stolen goods, though, so it led to a bit of a bru-ha-ha where Francis publicly disowned his father and was taken in by the Church. And then he founded the Friars Minor and the Poor Clares and did a lot to restore the integrity of the Church in his day.
But back to prophecy - the dual meaning of the word 'church' is integral to that story. It means both a building, and a community of believers. You can rebuild either, but in different ways.
Whatever message Fingolfin receives needs to be open to interpretation, and preferably would work on multiple levels. Fingolfin can't be wrong, and the Valar can't be liars.
So, to begin with 'Morgoth is not unassailable.' This is a true statement. Morgoth will be defeated in the War of Wrath. And even in the duel with Fingolfin, Morgoth will be permanently injured. The statement itself doesn't command a course of action or make any promises. . .but there is a strongly implied indication to act there.
'The Siege will not contain Morgoth' is another true statement of prophecy. The Siege will be broken imminently. We aren't going to be let down by this warning - there is immediate pay out. It gives urgency to Fingolfin's desire to act.
Another element of the message should be that 'True hope lies in the West'. This obviously parallels Ulmo's message to Turgon, but also is one of those unrefutably true statements. Is it a promise of aid? Not...really. But if there is any indication of when that aid will arrive, it cannot be a cheat. Eärendil is Fingolfin's great-grandson. But if this were pointed to Eärendil, it would involve Ulmo. So, rather, I think it should come across as a warning that the Noldor are on their own. If someone says they will not help you until the stars fall from the sky, you don't look up the timing of the next meteor shower...you assume they aren't helping. So if it sounds like a refusal to help, but actually reveals the conditions under which they would help...that might work. Something like, 'The Valar will not aid you while the sundering seas divide you and them.' Fingolfin could think that his suicide mission puts him on the correct side of the Sea to plead his people's case, in a 'if you strike me down...' way.