The answer to the first question: Joseph B. Polley, a collateral ancestor of mine.
Edit - Although your ancestor was part of the Texas Brigade and did write a book after the war, he doesn't appear to satisfy all of the other clues. Even if he did, in order to receive credit for a correct answer, you would have had to name the book that he wrote.
Bonus: CSA Brig. Gen. James McQueen McIntosh (1828 – March 7, 1862)Killed at Battle of Pea Ridge
and his brother
Union Gen. John Baillie McIntosh (June 6, 1829 – June 29, 1888) Lost his leg at Winchester
I've decided to take another break from trivia. It's just too hard on my blood pressure! Good luck, everyone! I may pop back in occasionally if there's a question I can answer easily without hours of searching!