It's not lack of clarity that inhibits humanity living forever. It's what we know now. We can record the entire universe from beginning to end. We cannot leave it, as that is a possible fallacy, as a) Other universes are hypothetical, and b) There is no medium to travel upon it to reach the new universe. A more feasible idea would be time travel, but that would require either a) infinite power or b) no mass.
I'm afraid not. The basic outline for the future of the universe is:
In 100 trillion years: Star formation ceases. All Hydrogen capable of coalescing into stars is gone. And the Stelliferous era ends.
100 trillion years- 10^40 years- The Degenerate era. Galaxies no longer exist and only Red, Brown, Black and White Dwarfs remain, remnants of the Stelliferous era. They remain for so much longer as they burn at such a lower rate to stars, but it would be very hard to sustain life on them. Proton decay causes era to end.
10^40- 10^100- The Black Hole era. Matter no longer exists. Black Holes remain, slowly evaporating due to Hawking radiation.
10^100- 10^1000- The Dark era. The universe is only populated by photons, leptons, electrons and positrons. Once they all reach c, in terms of expansion, time no longer exists and the universe dies.
This will happen because it is ultimately more likely to happen. And that is due to the second law of Thermodynamics, and the arrow of time.
Impossible. We literally cannot exist in another dimension. We cannot even imagine another dimension. It is literally beyond comprehension, it would be like trying to explain going up to Pac-Man, who can only mover forwards, backwards, and sideways.
Impossible once again. Dimension are the frame on which things exist. You don't become one, they were made in the Big Bang. And you cannot exist formlessly. Every memory you have, exists within your brain. Your brain has a physical mass.
Matter and energy are the same thing. And we understand them well enough. They trip you up now and again, but it just gets added in.