Q#1: Why are such differences presented?
Every language has synonyms and synonymous expressions. We use these because using the same expressions again and again is boring, and is often seen as a sign of a poor writer. If I want to communicate the idea that my mother's age is 48, I can say, "she's 48", "she's 48 years old", "she was born 48 years ago", "she's two years shy of 50," etc., each expressing the same thought. You do the same thing: when wanting to refer to what the text in Genesis say, you once say, are shown, once is given, once what I read includes, and once I see. These expressions all communicate the same idea. Therefore I understand that while the wording of the expressions differ, you do not intend for me to read any significance into the fact that you have chosen four different phrases to express what is substantially the same thought. This is also the case for the expressions used to indicate the ages of Terah, Abraham, Sarah, Isaac, Ishmael, Jacob, and Joseph.
The total ages are given in Adam through Noah for emphasis. Although the ages are easily calculable, the author wants the reader to think through exactly how long people lived. For instance, Adam lived over halfway to the flood. Methuselah died the same year as the flood. Everyone lived extremely long back then. Etc... This is not as important after the flood, as lifespans rapidly decrease and become increasingly "normal" - the author did not think it as important that the reader consider the lifespans of Noah's descendants.
Esau's age is not given for the same reason Laban's age is not given: it simply isn't relevant, because the Abrahamic promise is through Jacob. (Ishmael's age is given because though the full Abrahamic promise is to Isaac, Ishmael lives "before God", his daughters are further involved in the story, and his offspring are promised to become a great nation.)
Q#2: Why is Sarah the only female with an age presented?
Sarah's age is probably given both to emphasize the miraculous nature of her pregnancy, and possibly because she is a "heroine" of the story, being oft mentioned and oft praised. In addition, knowing that Sarah begot Isaac at age 90/91 and died at age 127, helps us understand the nature and timeframe of the search for Isaac's wife Rebecca and her "comforting him concerning his mother" when he was about 40.