The hen pecking others as described sounds like normal, reminding everyone that "im the boss" pecking order stuff.  Thats normal and fine so long as its not excessive.  Her "standing her ground" to the rooster would be ok with me.  But the rooster's increasing aggression is a problem.
   His age is a contributing factor as he reaches sexual maturity his territorial instincts increase.  The desire to protect his flock and drive off intruders is something that we find useful.  These are also "normal" behaviors but when they become excessive to the point he is causing injuries or demonstrating towards people, its unacceptable,  IMO.
Since roosters offer little benefit and are unnecessary in most backyard flocks, hes the expendable piece of the puzzle.