The Magician's Tower

Monster mission loot, Ice Crystal Staff, has a Circle of Mana aura. Circle of Mana aura effect says, "Slot 1: Decrease spell mana cost by 4%". Circle of Mana effect goes in the short buff box. Does this effect stack with worn mana preservation items that also say "Slot 1: Decrease spell mana cost by X%"?

Yes. Worn effects typically stack with spell effects and aa effects. The only things it likely won't stack with is Glyph of Arcane Secrets and Mana Preservation Campfires.

http://everquest.allakhazam.com/db/spel ... spell=8997" onclick="window.open(this.href);return false; says it is mana reduction on Companion's spells?

IblisTheMage wrote:....... says it is mana reduction on Companion's spells?

which I think refers to your group's spell casting