Can't answer all of those in a 90 word space, but let's get you started.  Barack Obama writes of being heavily influenced by two people, his mother and his grandfather.  Having only seen his father on two occasions, his grandfather became his substitute father.  His mother raised him, with their help, and took a direct role in his education.

The only negatives I can think of from his mother is that she remarried and then moved the family to Indonesia for a few years when he was pretty young.  While it was part of his formative ears, along with the loss of his father, that had to be pretty traumatic.  Guess he turned out OK though, huh? Good question.