Do you believe that there could be a parallel universe where everything exists as the opposite of this one?

I believe in the possibility but not a hardcore believer.

I believe that somewhere out in the endless Universe there exists other life forms.

No. It might have been a good subject for movies, but I simply can't imagine there's another me somewhere out there.

I believe the possibility of another life form somewhere out there, since universe is huge, but even then, I already doubt the existence of a life-form which is the same or similar to the one we have here on earth.

I believe, however, in time travel. Since time is not a straight line, but a bit bumpy and knotty and somehow, somewhere there has to be a way to break the puzzle. To be able to do that, we have to be able to define the variable of other dimensions, other than length, width and depth. Until then, I'll let Doctor Who do it.

Maybe. But I won't put much stock into it. For the most part, I believe there are millions of universes out that and that at least one of them has life.

I won't deny the possibility but worrying about it isn't what keps me up at night.