I agree with British astrophysicist Brian Cox about the frequency of intelligent species occurring in the universe. He thinks that there are two or three per galaxy.
So the Milky Way might have another civilization but Andromeda, which is a much bigger galaxy might have more.
Regarding death, I, too, think that oblivion awaits us when our consciousness subsides. As Edgar Allen Poe said, we experience little slivers of death every time we go to sleep. Also, when we’re anesthetized we experience oblivion. Death, to me, is like being anesthetized but never being brought back to consciousness.
Regarding consciousness, I think it happens in all creatures in varying degrees of sophistication based upon the complexity of the being’s stimulus processing capability. We, of course, have the most complex stimulus processing capability in the known universe. So complex, in fact, that it can be self-stimulating, as with reason and thinking.
I also think that each of us has been conscious multiple times and will be multiple times going forth in time. Not always as humans, of course, and certainly not as reincarnations of past human lives. Rather, I think that we have been, and will be again, all of the creatures that have been and will be in the future, from a blade of grass to the grazing animal that ate the grass.
I don’t think that memories of those experiences are magically retained and passed on to the subsequent creatures that we become. I think it’s a crapshoot as to which being we will be.