What's the point of Zada, Hedron Grinder? As far as I can tell it only interacts with Dark Dabbling and Long Road Home. In its stead I would conciser something like Mirrorwing Dragon that can trigger off your opponents spells, or simply run another defensive effect like Solitary Confinement. That being said I feel that this deck is trying to be more of a tokens deck, rather than a pillow fort deck, with effects like Adriana, Captain of the Guard, Carnage Gladiator, Havoc Festival, Hanweir Garrison, Mardu Ascendancy, and Behind the Scenes to name just a few, are pushing you towards a much more aggressive game plan. To this end I would probably be looking shift the focus away from mediocre defensive cards like Marchesa's Decree and Protector of the Crown in place of anthem effects and further token generators.

Instead of the Cluestones maybe try the cheaper (and therefore almost always superior) signets--i.e Boros Signet, Rakdos Signet, Orzhov Signet--and/or the keyrunes--i.e.Rakdos Keyrune, Orzhov Keyrune, Boros Keyrune--which can become creatures. Darksteel Ingot and Coldsteel Heart are also possibilities. Chromatic Lantern should be an auto-include in a three or more color deck.

The lands could also use some work. In addition to Rakdos Carnarium you might also add Boros Garrison and Orzhov Basilica. Temple of Silence, Temple of Triumph, and Temple of Malice are good budget options at < $1 each. Other good cheap options are the check lands--Dragonskull Summit and to a lesser extent Isolated Chapel and Clifftop Retreat--and the pain lands--Caves of Koilos, Battlefield Forge, and to a lesser extent Sulfurous Springs.