First many Christian scientists believe evolution is a valid theory, way more than believe in creation. That completely ruins your rhetoric that its a conspiracy by atheist to discredit the existence of God. You claim that nearly all mutations are detrimental to a species survival but in fact most mutations are neither detrimental or beneficial. What mutations are detrimental to a creature will kill that creature off and what mutations, such as a resistance to pesticides for insects, will increase their survivability. As time goes on those populations increase and those without the benefit of said genetic mutation will slowly die out, evolution in action.
Notice when you said kind in reference to cats, that could be considered a 'kind' but species no. Macro evolution starts at change from one species to another as we see in this instance.
Ring species have been observed in scientific studies under laboratory conditions and has been proven over and over again. As to your argument are you just saying that everything came into being between 6000 to 10000 years ago to defeat the concept of evolution or are you saying that evolution is claiming that God doesn't exist? You could always have the argument that abiogenesis did not happen but that God created basic life and that that life evolved in the system that God set up? Evolution by it self does not have to exclude God.