None of this really matters because only depressed people worry about the "meaning" of life, primarily because they have been denied all other sources of "meaning" and therefore cling to the one thing everyone (including themselves) has: a life. It's only human to grow attached to things and our lives are our most priced possessions after all.
Can you expand on the only selects one philosophical zombie? I don't really understand what you're attempting to express.
I think all people "think" about existence at some point. Maybe sad people think about it more than others.
If universes get reborn ad infinitum, nothing is that final.
I'm an exmormon/agnostic that believes in afterlife just not deity. I don't believe 100% just that it's possible, but that there's no pre-requisites to get there and no conditions. Mainly energy that is our 'soul' lives on in some form, or maybe there is quantum imortality where you keep being reborn in 'yourself' in another parallel universe and you retain some memories/essence of your former self, but are always trying to become better.
You or someone else could have a child in one universe, not the next. So in some universes you're never even born, some you are, and some people may be born for the first time ever, thus the whole old-soul/new-soul thing. Who's to say though it's not the same universe just it swings back and forth like a pendulum and when it's in the low arc it's our small time here, when it's at the high mark it's sucked back into a dense ball, then it explodes again on the downward arc...
I just can't buy that an all-knowing all-powerful being created everything (if anything it was an idiot who blew up all space/time toying with technology they didn't fully understand). This same being is petty, manipulative, and narcissistic and demands our fealty, our faith, our worship else we be cast into a pit of fire. Sounds like something Donald Trump would say to pretty much any Democrat or anyone who doesn't think his shit is made of gold.
Though the entire universe could just be like a wave that spreads out, and then back in and back out and back in eternally. Whether each iteration is a mirror of itself or 100% different nobody will probably ever know.
I don't think we'll ever have answers even if we colonize the entire universe. There's a good Asimov short story on entropy where they keep asking a super computer if they can stop entropy and for eons it keeps saying unable to compute and just before entropy runs out it came up w/ a solution.
Mankind became immortal (or long-lived at least) and had populated the entire known universe. Damn, I'd love to live to see that.