The Bible presents the issue of creation in a very straight-forward and clear fashion. God created the world in six literal 24-hour days. The issue concerning Dinosaurs existing before men is speculative and dependent on presuppositions that are arrived at by means of evolutionary perspectives. In fact, the evidence which "proves" that they did exist millions of years or even thousands of years before man is fallacious at best. There is fossil evidence, for instance, that they co-existed (footprints of both men and dinosaur together).
The concern regarding incest and the children of Adam and Eve, allow me to make the following comments:
First, we believe that if Adam and Eve were merely examples, then the Bible would not have led us to believe that they were singularly created. Also, if they were only examples and there were other human beings present, when sin entered into the human experience, those who had not been guilty of sin would have remained sinless. Thus, the entire world would not have been cursed.
Second, the only thing that makes "incest" sinful is that command of God. Prior to the Law being given to Moses, incest was a common event - even in the lives of the the Patriarchs (Abraham was married to his half-sister, Sarah). When the Law was given to Moses, God then condemned it and henceforth, it has been sin. Also, when Adam and Eve's children intermarried, the genetic information was so pure that there were no negative ramifications (such as mental slowness or physical debiliation).
I trust these comments are helpful.