Your essay is indeed well-written, clear and coherent. And I agree that especially when we're thinking about the future of humanity, it's very important to keep in mind that humanity only exists from each individual's viewpoint.
However I do question your treating survival per se as a fundamental issue. I think it's unfortunate, for example, that such a high proportion of our medical resources are devoted to keeping old folks (like me) alive a few years longer, when so many other people aren't adequately cared for. And I don't agree that if someone wants to live millions of years, they should be able to. It would be a very sad thing, and I think very dangerous for the future of humanity, if we had to severely limit the number of children coming into the world in order to accomodate an ever-growing population of people who care mainly for their personal survival.
Death is a part of our lives, and we don't become fully human except by dealing with that fact. Further, it's not my notion of utopia that each person should be able to have exactly the kind of world they want. I've seen too many 2-year-olds lately whose parents don't know how to set limits, and those kids aren't going to grow up happy.
Finally, your list of priorities is puzzling to me, since environmental catastrophe seems so likely to increase the number of deaths due to natural causes and accidents in the not-too-distant future.
Please forgive me if my notes are miscontruing your intent.