I think if it's done early in pregnancy, & you have no other ways to solve it (If you can not provide for a kid, it's a danger to you and the baby to conceive the child, rape, etc) that it is somewhat justifiable

In regards to your first question, it depends on the stage of development. I would personally say the first trimester is safe to abort, as for beyond that I genuinely don't know.

In regards to question 2, this question doesn't really make sense to me. It presupposes souls exist. There isn't any evidence for this though. I'd say "souls" are irrelevant here.

"Would it not be wise to simply abstain from guessing and let babies be born?"

I don't think so. What if the woman doesn't want to go through the ordeal of pregnancy? It's her right, and we shouldn't force them to go through a medical procedure they don't want to go through.

If you define murder by ending one's life and further explain life as something which possess the characteristics of life, i.e. reacting to stimuli. An embryo develops enough brain for sight at the third week, and at the eighth week, sympathetic nerves have developed. The line between abortion and infanticide is drawn while the embryo has yet to develop an awareness towards its surroundings and a clear sense of pain. Therefore, it is advisable on account of the embryo that it is removed from the parent's body in the first fourteen weeks