That's what I understood from the CS too.
Lehko was apparently freed from his sins because the Chieftainess and her daughter 'bore' the sins when they were killed by the Yagudo. I believe Lehko is the son of the bow maker as well. Not familiar with the RNG AF quests tho..
but if this is true, then it probably also means that Lehko is not a time traveler? He doesn't really seem to be, although he knows everything that is going on, and just happens to be very clever and a formidable male mithra unlike normal males.
i think the only thing left in Windy's storyline is taming Fenrir and shooting the bow of light.
not exactly related, but I don't think they used the Cardians lining up at attention event (in the trailer) in the actual game.