It's reall scary to think that you might, at some, level, have some influence over a child's science education. What you are suggesting simply cannot happen. Period. Find me an example and I will start tithing at your church.
First case is utterly impossible. Biochemistry cannot accomodate such a scenerio.
Second case is true as long as the newly discovered organism is located in some isolated environment, such as thousands of feet underground, and has no connection whatsoever to other life forms. A silicon bunny would disprove evolution.
Third case is just silly. We might soon have designed organisms that follow different kinds of biochemistry. But look at the definition of life proposed for such frankencritters: they will not be considered living unless they reproduce and evolve. Note that evolution is an attribute of everything that is living or semi-living (such as viruses).
My second kid is 5 is in Kindergarden, hasn't been tested yet, but reads at an advanced level and just accepted Jesus
First case: "utterly impossible?" Funny choice of words. Lets say some carbon based life form out west does something stupid like inject silicone into their breasts. Silicone leaks into the body, perhaps interacts with a bacteria or a virus and through a completely bizarre but not quite impossible set of circumstances creates a carbon/silicon life form.
Impossible? I'd say it's more likely than carbon based DNA forming on it's on.
Second case: A silicon bunny is found isolated in an environment thousands of feet undergound. No fossil record can be found, but that doesn't mean it doesn't exist, as plausible reasons are quickly developed of what might have happened to the record.
Third case: Rejected apriori, despite the acknowledgement that we might soon design such life forms ourselves.