Pathfinder 1E Trickery Domain power--How much does Veil-like power do?

[Pielorinho]

My trickery-cleric (priest really, but who's counting) just hit eighth level, gaining access to this little beauty:

Master's Illusion (Sp): At 8th level, you can create an illusion that hides the appearance of yourself and any number of allies within 30 feet for 1 round per cleric level. This ability otherwise functions like the spell veil. The save DC to disbelieve this effect is equal to 10 + 1/2 your cleric level + your Wisdom modifier. The rounds do not need to be consecutive.

Here's the text of veil:

You instantly change the appearance of the subjects and then maintain that appearance for the spell's duration. You can make the subjects appear to be anything you wish. The subjects look, feel, and smell just like the creatures the spell makes them resemble. Affected creatures resume their normal appearances if slain. You must succeed on a Disguise check to duplicate the appearance of a specific individual. This spell gives you a +10 bonus on the check.
Unwilling targets can negate the spell's effect on them by making Will saves or with Spell Resistance. Those who interact with the subjects can attempt Will disbelief saves to see through the glamer, but Spell Resistance doesn't help.

So, a couple of questions:

1) Starting the Master's Illusion is obviously gonna be a standard action. Given the fact that the rounds don't need to be consecutive, however, what additional actions are needed? I can see three different ways to rule it:
a. A standard action each round to keep it going.
b. A standard action to dismiss it before you've used all your daily rounds.
c. A free action to dismiss it before you've used your daily rounds.

Is there any support for any of these interpretations?

2) If I disguise myself and my allies as houseflies (fine size creatures), do we gain +16 on stealth checks for being so difficult to see?
3) Can I disguise us as air, making us essentially invisible until someone interacts with us (which interaction will probably consist of us poking them with something large, metal, and pointy)?

Last session I used the power for the first time to attack some ogres that were a distance from us; we all turned into Crows, Murder Of, and landed around them, gaining a surprise round. I think that's legit, but I'd like to explore the power's reach.

 

[DrunkonDuty]

For your first question I'd go with C) a free action to dismiss the effect.

And I say Yes to both Questions 2 & 3.

It's a powerful spell, it should allow the for some powerful effects.

That being said Invisibility only gives a +20 to Stealth checks doesn't it?

 

[Pielorinho]

Thanks for the answer--appreciated!