Nothing determines your worldview-and the course of your life-more than how you answer those question
Not really. As an agnostic I answer "I dunno" to all of the above, and go about my business and live the best life I can. Since God doesn't directly communicate with us, then we have no objective way of proving that He/She/It exists. That's why religious belief is called faith, you have to take a leap of faith to believe.
Now I have a very Jungian view of "God", that God is consciousness. I believe that the concept of God is still relevant to our psyche, even though he may not literally exist. But those are deep waters for longer post.
We who believe in one God see all of creation as permeated with personality, packed with moral meaning, and filled with eternal purpose... Atheists, on the other hand, see reality as the product of mindless, impersonal, and purposeless processes.
These are drastic simplifications. Many atheists and agnostics can and do have lives filled with meaning. We do have a sense awe and wonder of the universe. This is what Einstein called "God". Existentialism, Buddhism, Taoism, Pantheism and many other belief systems give man purpose without a need for an Anthropomorphic god.
Morals are man made. You can see this in the Bible, as morality evolves from bronze age barbarity to the more compassionate teachings of Jesus.
If God exists as described in the Bible, then abortion, same-sex "marriage," embryonic stem-cell research, and so on are clearly wrong. If not, then whether they're right or wrong is ours to decide, and no decision we made could possibly be wrong.
If God exists as described in the Bible, then we have a whole host of moral issues to deal with, because much that is perpetuated by him in the Bible is reprehensible by any decent moral standard.
For instance, since you mentioned abortion, here's a relevant verse:
Happy is the one who takes your babies and smashes them against the rocks! Psalms 137: 9
That's just one example, there's a lot more genocide, polygamy, abuse and other immoral examples. But I want to keep this post short!