1. Are we alone? I don't believe so, and I find it mathmatically impossible to think that we are.

2. Do you think we have ever been contacted or visited by a species not from this planet? On the fence about this, it's just as possible as improbable.

3. Do you think we will ever meet a species not from this planet? Yes

4. Do you think humanity will ever successfully spread from Earth/the Solar System?...as in self sustaining communities on other planets that could continue if Earth was no more? Yes

5. Do you think 3 or 4 will happen in your lifetime? No and the reason why is this, what we can see now out in the universe is what happened eons ago to that planet or system or whatever. We are looking at the past.
The concept works in reverse as well, lets say another intelligent species is also looking to answer if they are alone in the universe, they are watching our solar system and see our little planet as a possibility to colonize in the future. What they are actually seeing, depending on how far away they are, is hundreds of thousands of years or even millions of years into our planets history. Life may not have formed on our planet yet by the light rays their planet is receiving, this is what makes the concept of finding life in the universe basically like winning the interstellar lottery. Until we advance our society and technological know how to the point of actually traveling those distances and seeing firsthand if there is life, we are just reading last weeks news basically IMHO.