Belsaros

Can't include references right now, but I think what Dalinar is doing is more of an option 4, though close to option 3. He is forging a new "Adonalsium" rather than reforging the existing shards back into the old Adonalsium. I strongly suspect that the force that opposed and shattered Adonalsium was none other than Tanavast, Rayse, Edgli, Ati, Leras, etc. I suspect that "Unity" is not a new intent for a new Shard, but rather a fledgling of whatever Adonalsium itself was.