in chapter 8-16 do henry's thoughts and actions illustrate some basic tendencies that all human beings have?

Sure, much of this has to do with the thematic nature of the book.

Is running away from most certain death, as Henry did, cowardly or common sense?

The unspoken fact that most men run away from battle their first time speaks volumes about the human condition.

THe fact that there are no heroes in war, only survivors.