Spells must be prepared before being channeled. You can't skip the preparation step and put this spell into play channeled if you're not a Mage Noir.

Each target will receive their own instance of damage. 5 targets thus mean 5 times 1 damage. Each of these instances of damage will be enhanced by spells like "Burning robe".

You may not choose the same target multiple times, you may only decide to inflict additional damage to it.

Each target will receive their own instance of damage. Being multiple instances of damage, a player controlling Permanents with the Protector keyword may redirect each instance independently from the other ones.