At any point along the continuum from conception to death he or she is fully human and has the appropriate attributes he or she should have at that point in the life cycle. That isn’t conjecture. That is scientific fact based on evidence.
We only get one shot as we are each genetically distinct. Never again will that person be created.
A building begins with a blueprint, then a hole in the ground, etc. At any point along the continuum from planning to completion, that building and has the appropriate attributes it should have at that point in the life cycle. Would you consider that blueprint to be the same as a finished house? Could you live in that hole in the ground? That blueprint (DNA) may have all the information needed to assemble a house but it is not a house.
As for uniqueness, you seem more fixated than even God. Miscarriages and infant mortality were very common throughout much of human history.