[WoB compilation about spren]
Hmm. With a casual glance, I see at least one here that I might have been fixated on a question that wasn't actually being asked. I do this occasionally, particularly at signings, where we're going so fast and I think someone is asking something that they're not.
In regards to there being spren bonds before the Last Desolation--there obviously were. (We see Knights Radiant in Dalinar flashbacks that are before the Last Desolation.) I think I was trying to talk my way around a different question, without giving RAFO answers, that I'm not going to get into now.
Another sketchy one on this list is regarding whether the spren call the nightwatcher Mother or if they're calling cultivation Mother. I don't think the text of the books actually implies either way, despite what I said. (Unless I'm forgetting something.) For those in the know, with the Nightwatcher being an analogue of the Stormfather, that implication is there--but I don't want to confirm it either way. You'll get more on the Nightwatcher and Cultivation, and their relationship, in the books.