Thats a lot of analysis.
But I think you are missing the most important factor.
BB drafts a player. He doesn't draft a stereotype (speed rusher, run stopper) he drafts the best football player he can get.
IMO, there is 1 missing element in this. In the 1st round, BB drafts the football player with the highest floor. What is a floor? It's how good the guy will be if he doesn't improve. By definition, any OLB conversion project's floor is that of a 3rd down pass rusher. And BB doesn't draft those in the 1st round. I think this is going to hold true until either (a) BB decides to change his strategy one time on a high risk high reward guy like Mathews or Gholston, or (b) he just happens to find a guy who's almost ready to step in as a 3 down OLB. Most likely though, he will continue to fill the position with FAs and mid-round draft picks.