So many questions, so little time. Real life, in the form of my cats, is insisting that I pay attention to it, but I want to address some of the ideas you have raised.

First, unless physicists are very wrong about the speed of light being a limitation, we won't be able to effectively operate machines at great distances. Response time lags of several years will make that impossible. We will not be able to explore the universe from the comfort of home.

A more likely solution to the frailty of human bodies would be human-machine hybrids. At their most extreme, such hybrids would consist of a brain controlling a mechanical body designed to sustain the brain and to protect it from the thousand natural shocks (and ionizing radiation) that flesh is heir to.