Nickhere- You write very reasoned and thoughtful analyses of the situation...up to a certain point. Then your admitted biases slip in..

"Problem is, in the case of abortion, control is being extended over SOMEONE ELSE'S BODY. What about that person's own right to have 'control over their body'?" ...Here there is the implicit assumption that there is a 'someONE else', which is the point under contention! Certainly there is noONE capable of offering an opinion. If there is no way to logically or medically or religiously to resolve the issue, what way is there other than to allow the parents...specifically the mother...to decide in each case....with such as they may choose guidance from both doctors and 'spiritual' advisors?

"The 'pro-choice' lobby seem to regard the unborn child as a clump of tissue, a by-product of bodily functions...basically like a piece of s***."
...Now this is pretty heavy and loaded language! Those who advocate 'choice' are not a monolithic group. There are many reasons that a person can advocate 'choice' over having no choice....and only a fringe group takes an extreme view such as you describe. "...a piece of s***"???
Come on! I KNOW people who have worked in the pro-choice ranks, and none of them have taken such an unfeeling, hateful attitude. They were caring, concerned folks, trying to find a path thru an unfortunate situation!

I have seen, over & over, the point made that IF someone feels that "life begins at conception because God breathes a 'soul' into the embryo then", they MUST feel obligated to oppose abortion.

*Sigh*...yes, but in many areas of life there are differing opinions about 'moral obligation' and how and when is it ok to express it or demand it. I have tried to make the point that SOME of these situations require allowing involved parties to make their own decisions.....
Now, I have had replies to the effect that "So...you would say that Nazis who 'believed' that Jews and others were sub-human, really had no moral constraints about killing them?" POOH! I have many paragraphs of detailed Philosophical explanation about 'exactly' why that is a flawed argument, but it shouldn't be necessary to type them out. It IS different to condemn and kill masses of people for political reasons than to make a decision not to allow a zygote to develop....
Yes....I KNOW it is difficult to draw a line precisely as to where 'terminating a foetus' ends and 'killing a baby' begins...I know because I had to help make that decision once...and it was painful beyond belief!!! Look up 'triploid cells'...

I'm sorry, but you cannot write a rule in these matters that covers anyone but YOU...and you can't guarantee YOU will ultimately be happy with it.