1. Yes. Dead organisms are similar to non-living objects since do not take in nutrients/energy to offset the process of entropy in thermodynamics that enables them to maintain an organized system. Additionally, a dead organism stops to grow, does not reproduce and does not respond to stimuli similar to a non-living object.
2. No. With the continuing discovery of new species, the Linnease system is liable to continually change. Discovery of the evolutionary relationship between the discovered species and with already discovered species, enable the taxonomists to rearrange the cladogram to best and rigorously understand the tree of life.
3. No. Fact is that they are related. While they may seem very different phenotypically, and even genetically, they share, at some point up in the phylogenetic tree, a common ancestor. For, example, they share the same Animalia kingdom and phylum Chordata.