Subvisual Haze

The Stonewards being the exception seems highly unlikely to me. The Dalinar vision that we "see" at the Feverstone Keep actually only has two orders of knights present at it: Windrunners and Stonewards. There's two important implications from that in my opinion: 1) If you assume the vertical axis on the diagram of Knights Radiant Orders represents affinity to Honor (top) or Cultivation (bottom), then these two specific orders are the ones closest to Honor. It makes sense that Honor would remember their defections specifically, as he likely felt them the mostly painfully knowing that they were most honor-aligned of the orders. 2) There may not have been just one Recreance. It could have been a cluster of the various orders dissolving at slightly different times.

In a WoK epilogue we get told that Ati, the holder of Ruin's shard, was a kind and generous person before his shard presumably bent him to its entropy-loving will. That got me thinking, why would a kind and generous person take up the shard that loves destruction? Assuming he didn't just get stuck being the last person to pick his shard from the Adonalasium-corpse raffle, I can only assume it was because Ati wished to limit the destruction that the Ruin shard was very capable of inflicting all across the Cosmere. Now Ati (hopefully) would have had an inkling that as time passed his ability to keep his personality intact and steer Ruin towards less catastrophic ends would be greatly impaired. So he had to build a prison...for himself. I think we have a WOB that Odium does not like to settle in a system, rather he prefers to keep moving. When a shard is in one place for too long, I suspect the shard begins to invest its power into the planet itself, effectively limiting the freely available power that a shard-bearer has at their disposal. The shard's magic-energy act like deep roots in a planet, if the holder of the shard tries to exit the system they're invested in, they will do so reduced as they'll leave a lot of their shard's power behind. So having an idea of how Odium would prefer to operate to maximize his power, Ati decided to do the exact opposite with his shard. Although the most Ruin-y thing to do would be to jump around the galaxy kicking over the various sandcastles that the other shards had made, Ati instead made a pact with the bearer of shard perfectly opposite to his own to create an entire planet. This not only bound up most of Ruin's power within the planet itself (he likely had to spend a huge amount of his power to create a planet instead of just settling there), and kept him stuck in one place, but also locked him in with a shard that would by sheer reflex oppose any of his attempts to cause widespread destruction. It's no surprise that Ruin was so angry and frustrated by the time the events in The Mistborn Trilogy occurred, his power being imprisoned and his will being constantly opposed was the system working exactly as intended. Scadrial and everything on it were Ati and Leras' mutually constructed prison to keep Ruin from spreading destruction all across the cosmere.

Yeah, Eric's madness reminded me a great deal of how Vin would hear the twisted influence of Ruin in her thoughts. Eric's strange thoughts encouraging him to abandon all attachments certainly points towards the shard influencing him being something like Autonomy/Freedom. Indeed, intrusive thoughts like this would do a perfect job of explaining (Shadows of Self speculation)