My Thyphlo Ruins experiment ended in failure; the torches, when lit with a blue flame, still light up red.
So next idea was to take a blue flame from Hateno to Lurelin, but that's not very impressive of a feat. So I had the idea today to take it even further than that and try to bring it to Eventide Island. I've already determined that if you drop a lit torch it stays lit, a korok leaf cannot blow out a torch, and a torch will not roll off a raft while sailing. So, it's possible in theory. Once again, it's all up to the weather.