I applaud your attempt. I would argue that #4 gets into a rather dangerous and often-ignored area...namely that one of the big misconceptions about child support is that it is a "I get to see my kid" fee. It isn't. The issue of a parent's financial responsibility to a child and their suitability to have contact with that child are, and must be, separate concerns. I would support government funding of DNA tests to prevent men from being forced to pay for children that are not their own, but I would want there to be some provision to protect a woman from "that was fun, see ya, tough shit" circumstances. If you're willing to take measures to prevent entrapment of men by women, you have to concede that women get used and lied to as well, and would need some measure of protection. "Be safe or be sorry" policies need to run both ways. Men need to share equally in the risks associated with sex. Biologically, women will always carry an increase in certain risks and costs, so I consider it fair that their rights be more extensive as related to whether a pregnancy need or need not continue. A man who really cares to see a child born has means of making it worth a woman's while without resorting to nine-months of government-sanctioned imprisonment (which is what it would take, both figuratively and literally).
I have a good reason for being strict in this we cannot be sure when a human is alive. We are not talking a dog we are talking people the only species line with self-awareness and sentience we are aware of.
I would like to point out two things in these sentences that, I feel, help to explain my feelings on the whole "what the hell is life anyway" subject.
The first sentence, in substance if not in spirit, I agree entirely. But saying that we cannot be sure when a human is alive can not logically defend a mandate that it be assumed to begin at one point over another. It only defends agnosticism.
You follow that with talking about dogs, and how humans are the only self aware (to the degree that we are capable of knowing, which is only whisperingly better than our ability to objectively determine the beginning of "human" "life" for however you would define either of those terms) beings in existence. I'm sure many dog owners would disagree. As would many people who work with chimps, etc. Setting the bar at "sentience" and "human" begins to demand a definition, and those definitions are very very tricky. If you set it at language or other self-expression, then many kinds of disabled people become non-human. Because it is a hard and uncomfortable question, it is tempting to try and answer it emotionally, which is even more dangerous.
I do not mean this next to be considered a compelling point of logic, and I don't mean to offend you so I hope you will be charitable. It might be worth your while to reflect a little further on the subjectivity of your feelings in this matter, and whether that's a charitable and humane way to determine policy for millions and millions of situations that it is arguably arrogant to think you can, as an individual, begin to intuit in all their complexity. As you say, we cannot make a meaningful definition for life until we get to the very very small scale of cells or the very very huge scale of biospheres, which makes it unkind to insist on your own arbitrary definition for all people.
I tend to try and define the situation from the other side. I find death more easily understood than life, and I think we have some decent societal guidelines for what we will tolerate, relative to the necessities of both justice and governance, where suffering and death are concerned. We know that zero-tolerance for allowing suffering and death is unworkable. The two things are inseparable from the complex processes of life and living. Generally we get by by setting some minimal degree of tolerance for situations where we can allow or inflict suffering and death in an attempt to balance the rights of individuals against the needs of the population. It is the best way to accomodate logic and knowledge (along with its limitations) as well as emotional considerations. When setting policy for a society, when taking emotions into account, you need to look at ALL the emotions involved in an issue...the empathic sense of wrongness in deliberately killing someone or something must be balanced equally with the empathic sense of justice and social safety when determining if it is acceptable to kill a sociopathic murderer or control animal populations, just to make a severly over-simplified example.
Which is why I would advise more careful thought on your part as regards your emotions. As a mother, I affirm whole-heartedly that your feelings about the preciousness of babies, regardless of any knowledge we can have of when that status actually begins in the eyes of objective reality, are as valid and right and good as any of the feelings that can be brought to bear on the subject at hand. But consider, being who you are, as a woman with no inclination towards sex with men, it is more than a little likely that you cannot weight with sufficient empathy the validity of the feelings of women who would be subject to the laws on which you would insist.
While I am careful to remain open to the possibility of new evidence and insight, when I weigh every variable I am capable of considering at present, zero-tolerance-except-in-very-specific-cases is both socially unworkable and morally insupportable. It simply does not serve to effect the practical reality that your moral imperative is seeking, and the emphatic-full-stop of "murder is wrong period" is morally incomplete. In general, a real stance of "pro life" is only cut and dry for people with an unjustifiably narrow definition of life.