I suppose you are alluding to the homuncular regress problem.
I won't go into the rest as it's off topic here.
It's not clear how evolution can explain consciousness and similar goes for any emergent property.
Evolution in the form of biological requires emergent properties. An arm is an emergent property. At its reductionist level its just atoms, but through the actions of genes operating in a certain environment those atoms are arranged into molecules, proteins that form an arm and so on.
Since all traits are emergent, since biology works through developmental processes, it is not clear how you are viewing evolution as having difficulty with explaining emergent properties: that is, in a sense, what it actually does - explains a particular category of emergent properties under the category of 'life'.
So if dispositions are emergent properties from chemistry and physics that seems independent of evolution.
Evolution is the explanation of how chemistry/physics in a certain arrangement have come to form the diverse life we find on the planet. The emergent properties arise - and those emergent properties which, on average, lead to the reproduction of more entities with those emergent properties than those without said emergent properties, increase in frequency in the population of aforementioned living entities.
That's how we explain the nature and distribution of adaptive emergent properties. Not all evolution is adaptive, incidentally.
What I am saying overall is what seems to be happening on the theory is a body is gradually created by mutations then it either survives or it doesn't but it's not clear why all these little changes happen and all these emergent properties and mechanisms arise
It certainly isn't clear. It's a complex subject. It not being clear is not an argument against it.
Life develops over time, small changes at the start can lead to big consequences later. It can be difficult or impossible to predict those later consequences - it is a chaotic system - but it's also not completely mysterious. The development of a lifeform - more easily understood in multicellular life, but not limited to it - is governed by two primary factors: The environment (which includes itself!) and the genome. Obviously much of the environment is not actually heritable and so is not that which evolves through natural selection. The genome however, mutates, and the way the mutated genome interacts with the environment can lead to differential reproductive success of resultant entity - the conditions for evolution to occur.
Personally I am a gay anti natalist so I am kind of the antithesis of the official narrative.
Your sexual preferences and opinions about the value of birth may be uncommon, but for what it's worth - their existence does not stand in opposition to the thesis of evolutionary biology.
Nevertheless I don't see how evolution explains this property or predicts or ensures it.
There is no Theory of Consciousness. Without a consensus on what Consciousness is, what causes causes consciousness - it is not surprising that we don't have a specific answer as to how it came to be. The question then is, so what?
I am sure natural selection would select something as rich as consciousness
How can you be sure?
For all we know what was being selected was higher order thinking. The meta cognition of thinking about thinking and thinking about thinking about thinking - which in turn may have arose as a function of social need - understanding what others are thinking and what they think you are thinking and what they think you think they are thinking. Which might lead to a state of awareness about ones self that we have come to call consciousness.
Thus - consciousness itself is just a consequence that arose because other properties were being selected for that resulted in it. How can you be sure this is not the case? Since we cannot agree on a Theory of Consciousness - how can we say it isn't a spandrel?
It seems nature and chemistry/physics gives a lot of free gifts to evolution for it to work with.
Looking at the epic pile of dead bodies that are left behind makes me think maybe 'free' isn't the right word here. There are gifts, but in order to 'find' them - requires a lot of wandering about in 'genespace' - and a consequently large number of deaths - so they are certainly paid for.