This is a FAQ. So what are you looking for some kind of percentage or odds? There are none which are universally agreed upon. The only thing you can expect with this question are opinions and beliefs. Neither matters much in settling the topic.
The requirements for life are numerous. You have only touched upon a few. We could include galaxy types which would not be conducive for life, galactic habitable zones, types of stars, stellar variability and fluctuation, binaries, orbital eccentricity, gravity which holds a suitable atmosphere, a magnetosphere, volcanism, plate tectonics, even the balance between oceanic rocks which helped stabilize the atmosphere with an ever growing Sun helped to allow for life despite Milankovitch cycles which seem to have enclosed our planet in a snowball twice etc etc.
Believers have their own reasons: the Universe is big; I saw aliens on a movie once; I read that aliens exist in a supermarket tabloid or in a ufo book or on the internet; god must have made aliens; etc.
As for life on Earth, the estimation is between 800 million and 1 billion years left before water boils off of our planet.
Wormholes are a topic of science fiction. Sometimes mathematics allows for things to exist which cannot exist in our physical Universe. Wormholes fit this. Wormholes are void of matter. When they interact with matter, they disintegrate. To exist, wormholes must have been created in the beginning of the Universe and there are no indications that this ever occurred. They violate the second law of thermodynamics. Yet, as always, you will have the believers because they saw it on a Stargate episode on tv.
There is no reason to feel one way or another about the existence of alien life. Give one example of how it affects your life? Because you are lonely? If aliens exist 2,000 light years away and have no way of interacting with you or future humans ever due to the distance then how does that affect your life or philosophy? What is sad and disturbing is how the public is misled into believing that contact is occurring when there is not a shred of evidence to support such beliefs unless you subscribe to the paranormal and require no evidence other than 'someone said...'
There is a reason mammals arose to dominate the globe as they did. They didn't do it by being passive. They killed for food. They were aggressive. This ensured that they survived. It's in our blood and part of our instincts. That's just how life works on the food chain. You didn't see bunny rabbits take dominance of the mammal world. We would expect to find the same aggression in any creature which dominates planetary life. Perhaps genetic manipulation could remove these genes from the future population but the chances of that ever being allowed to happen by a society are zero.
Nature is what it is. You can look at yourself in a mirror and wonder if a god made you and made aliens too. Or you can understand the big picture of two generations of stars dying before the proper metals existed for life to be possible and realize that if a god did exist perhaps a simple snap of his god fingers would have been better. Perhaps a snap of the god fingers would have not made a star which dies. Perhaps a snap of the god fingers would have eliminated the ever-threatening asteroids from deciding the fate of life forms. Or perhaps an all powerful god would have made his special creation immune to snake venom and viruses and the tsetse fly. That's the pathetic part.