Well the infiltrate targets might not be exactly who you think -
Wealthy noble - Usually situational and after its needed. If I can't surprise kill with Yuanshi it I don't give it away
Shiazarus - Obvious reasons
Shikana (Only infiltrate the turn I plan on Sac-ing her to force the morale damage onto the opponent)
I also imagine I use melosia a bit differently than you do. I don't really play this as an aggro morale specifically because I can't get mass fliers. She's really just there to add to the attrition damage through Radariah and set up for a final blast via Lingbao/Infiltration bombs. I tried running this as an offensive deck and it had way too many issues dealing with health damage rush decks. Melosia doesn't even come out until T5, at best and by then I have to deal with the field already in place. Melosia herself is responsible for only 15-30 morale damage a game which can add up quickly once you incorporate the other factors (Creature kills, infiltration bombs, etc.)
As for the other suggestions,
Cassial - Only have 2
Mysterious Box of Wonder - I think I could squeeze one in by substituting it with Jihani's wall.
Harbinger of law (Only have 1)
Spirit of the Ancient Guardians - I've been on the fence with this one. On one hand its good for getting easy morale damage in via kill, but on the other hand another 4 cost starts slowing the deck. I'm going to try taking out an intimidating monk and grounded angel and see how that goes.
Echo of the Battlefield - While I like this card and think it would fit in well the problem comes down to what I would have to take out to incorporate it and I don't really see anything that would be beneficial to the strategy. I know the easy thought is get rid of the infiltration mechanic, but in addition to the Creature kill and radariah attrition getting those nobles in for 10 or 14 damage a pop becomes notably important. Besides if I'm going for angel rush damage it would just make more sense to build an angel rush deck.
Balance - I can understand why, but the health/power differential among the creatures really isn't high enough to warrant it. Plus with all the angel hate out there right now, getting a strong flier though is easier said than done.
Gao Han - I wish. Wanna trade? xD
Adaptive Drone - Swapped it in for the chef's - they're too slow to really make a substantial difference.
I'd also like to run another melosia, but the one in the CZ is the only one I own so I'm running with it atm.