OK.
You have finally uncovered the big lie that the entire football world has perpetrated. Dick Lebeau was a terrible defensive coach. And it is only from the grace of Bill Cowher that he was able to do anything.
And in terms of pieces....your story doesn't hold up.
This is who was on the team in 1991:
https://www.pro-football-reference.c...991_roster.htm. So all those players are not Cowher guys. This is who was on the team in 1992:
https://www.pro-football-reference.c...992_roster.htm -- so Darren Perry.
Then, 1993:
https://www.pro-football-reference.c...993_roster.htm and 1994:
https://www.pro-football-reference.c...994_roster.htm where both Capers and Lebeau discuss how they pushed for Greene and Brown. I have also heard them say they wanted Seals as well.
If we go by your logic, Noll built the defense since he left Cowher et al with Woodson, Lake, and Lloyd. The only non Lebeau/Capers selection for the defense was Darren Perry.
And this is straight from your post: "
His development of the zone blitz isn't really relevant to this topic, did Bill Cowher build the Blitzbugh defense, or did Dick LeBeau?"
It is highly relevant, because again, the two dudes who ran the Blitzburgh defense (capers and lebeau) are on record all over the place saying how they basically decided after 1991-1992 that they were going to go "all in" on running zone blitz concepts as not part of the defense, but as the entire defense. I mean, I guess we can consider that the guy who invented it and was specifically brought over to teach the defense (why do you think they hired this failed coordinator?) had nothing to do with it.