Oh I completely agree. And those situations Are a large part of why I think mothers should be able to terminate their unborn babies for convenience as well. Calling unborn babies not a life is a cop out IMHO though. Obviously a fetus is alive.
It is alive but is it 'a life'? To me up to a certain point the foetus is only 'alive' in the sense that it is another part of the living mother. It really depends on what you consider 'life' to be, right? The foetus does not think for itself until a certain point and does not experience pain independently until another. Is it a life if it is not even capable of feeling its death approaching? Let alone understanding what death is? Surely the foetus is simply a part of the mother until it is able to think independently (even in the most basic terms). To me it would be strange to consider the foetus as 'a life' as it is not, at least until a fairly late stage, anything more than a part of the mother. It is part of her 'life' and she can remove it in the same way she might remove a wart.
Fetus is alive and shares chromosomes of both the mother and the father. Most of the points you made apply to newborn babies as well, including total dependency. Something that is alive is a life, by definition. All of your tests and qualifications for what constitutes a life are arbitrary, and I think speak directly to why society has such trouble defining life along a spectrum of development. I define it at the point where it begins, conception, and simply say its just not that valuable at that point unless the parents place a value on it, instead of trying to move the definition of where it begins for everybody else.