1) killer can have equal reasons. His reasons may be immoral, but can be the same happiness.
Killer: murder this guy, get 1 million dollars.
Victim:self defense, save my life.
Both people have pretty good reasons.
2) Best action possible again is not relevant to abortion necessarily. You seem to get caught up in thinking of the best outcomes are justification for abortion. I agree though, if the mom gets the abortion, the scenario will turn out better for the mom. However, outcomes do not justify the dominion over someones life all the time. In the case of abortion, outcomes do not give permissiblity for it. You cannot value the life of a fetus based on outcomes because then you start valuing all fetus' at different values. Like in math, example say y=x+x+x+x....the first x isn't different from any of the others, they are all the same. So, if we are going to argue outcomes, you run into a type of mathematical dilemma. What if having the baby will make things better over in this place? So, that fetus got lucky and this one did not? That is foolish thinking.
Killing old person: third party situation and thus can be justified. So, I have no opposition with that sentence.
3) You cannot claim fetus' value is easy to determine without evidence. We are arguing as if it is human. I will save a debate for the other way around in another time, but for right now, please assume fetus is human. I don't see how a human in a mom's womb makes it any less human than a mom.
4) First 2 sentences of the last paragraph: Yes, if there was a bomb, and YOU KNOW there is, then at least try to call for help. The dilemma is when people start assuming and then justifying which is why I don't feel this example works well.
Lastly, again outcomes/circumstances do not decide value in all cases. If you don't agree, please explain. The cases where it does apply may be a war effort in special circumstances.