I agree with wavedash, I think we should salvage 5 dim shields and 4 aether pillars.
Lobo is not needed, as we have mind flayers, and water doesn't have any creatures that are worth PU'ing. I mean, you could also just add an extra creature to your deck.
The only decks PU is usefull, in my opinion, are decks that rely completely on taking the opponents creatures, or that have creatures with some kind of growing ability, otherwise you could just take a creature instead of a PU in your deck.
About the discarding, I don't think we should discard a shockwave, because 5 shockwaves into one deck can be a real pain to fight agianst and taking one out of that really decreases your chances of drawing them.
For discarding, I think we should take a look after the decks for the next round have been built, to see which cards are (agian) left over, those can be discarded.