Well how to change the aura's should be pretty simple, you would just have to go to the first trigger, Totems Cast, and then go all the way down, there's a comment saying AURAS HERE or something, below that I set the auras to what they're.
Create a new aura, define the range of the aura in the object editor, make sure it is a unit defined aura, go to "Totems Cast" trigger and add it to the totem you like, SPELL_MISSILE1 equals the first totem I create. You can easily count them.
I hope you're able to understand this, else pm me your map and the a detailed description of what auras you want on what totem.
About the ice star, there is a way to make it disappear once a unit leaves it, or there's no units left on it. I could try to make that some time, but don't expect it anytime soon.