Well, regarding discards.
Let's look at the numbers a bit, should we? We lost three matches, potentially we can lose 4. That means at worse, we're going to discard 24 cards. We can convert exactly up to 24 cards each round. That means that, if we discard nothing but air pends / pillars (which WE CAN DO), we can convert them back. That means we can effectively CHOOSE what to discard, not looking at decks. So, why exactly should we discard anything but pillars and pends? If we want to discard OEs, we can convert them. Squids too. But we can convert pretty much anything, including salvages, including whatever we want to discard from those decks.
I don't actually see a logical reason as to why we shouldn't discard pillars and pends, as if we do we can do whatever we want, including what we would do if we don't.