cast/receive shadows on iphone- check box or uncheck box

i'm starting to optimize my iphone scene, and all my objects have the "cast shadows" and "receive shadows" checkbox checked. Since I am not using lights on my static geometry (the have lights baked in from maya, and my lights for my characters have 'no shadows' checked) do I need to worry about these boxes?

will these boxes turned on take up any processing?

Unity iPhone doesn't do shadows, so the checkboxes have no effect.

In short, no.

I'm assuming your lights cull only the characters (if not I'd do that since environment lighting is baked anyway), and since they cast no shadows there isn't a problem.

Logically, since lighting originates from the light itself, if they cast no shadows, the engine will never need to check whether or not the photons emitted will need to cast a shadow on an object.