Sorry, if I didn't read all 11 pages. Been a member for a few weeks now.
But here's a shot.
1. As far as I'm concerned morals are part of a greater concept, which is about rules that we need to abide to, in order to live in a given society. These rules have a history, whereby they have been tested on trial basis and have been filtered -- meaning the bad/ineffective rules have been discarded. What's left -- today's rules -- are those that have proven to ensure that our society functions more or less smoothly. So, notice that morality, being a part of these rules, is also a work in progress.
2. As an atheist, your question is badly constructed, since in my thinking, there is no God. What motivates me? Basically, in every living situation I have a choice, either abide by the rules -- that is, the present laws, moral practices, family values, etc. or not abide by them, realizing that there are consequences to my action. Also, I have the choice that if I feel that a particular existing rule is unfair, unjust, out of time, etc, that I can actively seek to change the law, the practice or people's attitude on that matter.
3. Immoral decisions? such as what?? If it is against the laws, that will take care of itself since there is a system in place to punish those who violate them. If it is a private matter, then it is up to me to see what are the consequences and if I'm prepared to face those.