Not exactly the same as the "simulated" brawl where all 30 cards are Zerus and starting mana is 1.
Disagree that discarding cards is OK. Discarding cards reduces the likelihood that you'll have a suitable play next turn. Card draw here is about maximising the ability to play on tempo.Cards in this brawl are just as important as cards in any match.
I agree; more Zeruses means a greater chance of having a minion that benefits you right then and there. Possibly they mean don't worry if your discarded Zerus, was a desirable minion, because it would've changed on the next turn anyhow.