This is a tough question. Mental pictures, like picturing a chair or table is not real. The people sitting around will see different interpretations in their heads. So that rules out a lot of pretend things that occupy time in the day. In order to figure out what is real in ones life, it helps to watch a day like a video and see what you do. If you spend lots of time on a subject, or worrying, or even on a work project, but it doesn't turn out to be worth the time, then it may not be real. I would say real would be what a group of people would agree on if they could see everything from every angle. But yet, that would assume things play out by a definite order. So less empirically founded, perhaps real is what happens, and what you make happen. It could be those things that do indeed turn out to affect reality in a solid way.

Good one haaha!

That's right, the theory of Relativity does break down and stop working at singularities. There is a view now in science talked about by Lee Smolin that blackholes are actual the birth of new universes with new laws. So in other words, there is some continuity in time between subsequent black hole collapses and expansions of universes. The same may apply to any gravitational collapse, and if the sun is a black hole, it must also fill these criteria. E=mc^2 seems pretty solid currently by experiments. But I sometimes wonder about the notion of mass staying constant. That's what gets me when I think 'bout gr.

Humans come from a source of information, from dna. The first organic molecules (ingredients for but not life itself) came from meteorites that came into contact with the earth. So we came from space, and in a sense, are ourselves aliens to the planet we call home. But just a group of atoms is not life, and fails to be until it can collect and reproduce copies of atoms that behave closely, and perhaps not too exactly, like the group of matter before it. So this a a molecular-evolutionary idea. It takes time!
But in order for these atoms or cells, or dna in the cells, to work together to stay together and duplicate in time, there must be a world which permits it. So I would say that liffe comes when matter begins to behave like we are used to, and sometime at which point time allowed for matter and energy, or info, to form at all. This is not necessarily at the big bang. One of the biggest mysteries at the heart of cosmic thinking now is that there had to be something before the big bang, and that we are just a part of the remnants of that event. I think that it goes beyond this, and that life really began when time first condensed matter into gravity relations. In my opinion, we are the after life or fossil of a previous era.