Nice research... I remember the whole thing with pain. The #1 overall pick came from the OJ trade with SF; everyone knew the Bills would go defense, the two top LBs were Cousineau and Barry Krauss from Alabama. Ironically, of course, neither one became more than a serviceable pro. Ironically, on of their #2 picks, Jim Haslett, turned out to be much better. That same draft also brought Fred Smerlas and Jerry Butler, which is not a bad haul considering they got nada for their #1 pick.
The Bills did much better with their next crack at the #1 overall, in 1985.... but you all know that story.