1. Because everything started from a single point.
AFAIAA there's no evidence for that. The
observable universe would have been extremely small relative to its current size (the singularity is not generally taken to be real, but a mathematical artifact), but the whole universe is vastly bigger than the observable universe, and may have been (and may still be) spatially infinite.
That's a rough approximation and not always correct - for example, a bottle containing half oil and half water has
higher entropy in the unmixed state than in the mixed state (i.e. when well shaken), whereas the opposite is true for coffee and cream.
How can there be a lot of disorder when everything is cramped around a single point?
As above, that's not a viable description - whatever it's size then relative to its size today, it was the
whole universe, and it was all very hot, very dense, and very uniform.
However, the question isn't so much
how we characterise the big bang state, but
why it should start that way given the time-symmetric fundamental laws of physics.
2. Quantum mechanics is based on the idea of probability. Probability itself is based on the idea that it is possible to predict things without knowing the underlying causes of the event you're trying to predict. Lack of knowledge is the basis for probability. It's no surprise that Quantum mechanics reaches the same conclusion as the assumption that probability is based on. It doesn't make a whole lot of sense. It is formulas with no good story to connect them. It's not a good theory.
Theories are based on their performance, not whether they have a 'good story', and quantum theory is by a long way the best physical theory we have in terms of the precision of its predictions.
However, my question was not about quantum theory per se - but about the best
interpretation of it, i.e. its metaphysical meaning.
3. A living being is something that can always grow. That's it. What you call universe, is always growing (Hubble observation). That means it is a living being.
Many things can grow, e.g. crystals, celestial bodies, polymers, sinkholes, etc., but are not considered living things; my question concerned what is generally be considered to be life/living. There are many definitions, but growth alone is not definitive.
Life started in the waters. Water looks blue from the outside but when you're deep inside of it, it is dark. Just like when we look outside our planet and we find ourselves floating in darkness. The story of life is packed into this planet from the start to this moment. But that is a copy of the original story. This planet is a seed that life grows out of. This seed can be planted elsewhere with modifications to create something different. So to sum it up, the origin of (what you call) universe is the same as origin of life on this planet. It started in the darkness. We can see it from the outside when we look at the beginnings of life in the oceans and we can see it from inside when we look at the sky.
This answers neither point in my question. I'm after at least one detailed abiogenesis sequence, and at least the ratio of planets with and without life. Naturally, I don't expect anyone to provide the answers today.
These are very short answers. I'll try to make some graphic illustrations to make the points better.
Please don't trouble yourself.