Hi,
If you send an event with a delay, then you are fine, no performance hit or free cpu cycle to free.
Also, I am not sure it's actually necessary to implement randomness in your loop, since anyway gameObjects will be processed in turn, not all at the same time ( it's a loop, not a common call fired to all in one go).
but of course, it depends very much on your scene and what you are actually doing to them gameObjects during that loop.
Bye,
Jean