We might not be unique in those senses. If DNA and carbon based life is the standard then we are likely more similar to most life in the universe even if we have small differences in physiology or culture. We don’t share a direct biological origin but we are still made of the same stuff, probably originated under very similar conditions, etc. Unique forms of life likely develop under equally rare conditions in exotic environments. We’re probably just run of the mill meat bags.
I disagree that Aliens even if we share the exact same building blocks would look similar to us. For example even for planets that would be habitable for us would have minor differences in atmospheric pressure, gravity, the types of radiation their star produces would result in drastically different evolutionary paths. Also even if there was a clone of our solar system evolution would be random and the life would look different from each other, I mean look at Australia, or even look at Earth's history the fauna during the Jurassic looks way different than what we have today.
Small differences here means within the realm of what’s possible to build out of organic molecules. We’re talking about averaging life across the span of a galaxy. By unique and exotic I meant unlikely life forms like Boltzmann brains or sentient planets. We are probably one out of a million sentient, organic, sexually reproducing species. Once you’ve seen a few thousands of these you’re probably bored.
