I would be surprised if they rely only on the front because they've lived in man all year and the whole defense is built around forcing early throws, throw aways, and bad throws. The defensive line doesn't generate any pressure on its own without Traore and Bothello, so sacks are a function of smothering coverage and chaos created at the line of scrimmage. I haven't noticed nearly as much safety pressure this year––at least two safeties coming from a two high look––and I think Golden's first year was the high point for that.
ND's passing game is passable so long as they stay on schedule. Leonard's ability to improvise is crucial and somewhat mitigates his own underwhelming arm and the years-long problem of putting largely underwhelming receivers on the field. He's basically having the season that Hartman did last year, but the difference is he can move the ball on his own.
Jeremiyah Love is probably the best back that IU will have seen so far, and the three-headed monster of Love, Price, and Leonard should push IU's run defense to the limit. I expect ND to lean on the run, and IU's aggressive run defense looks like it will be the most significant challenge the Irish have faced so far.
As important as ND's run game is to the outcome on Friday, I think the key will be whether IU can crease ND enough on the ground. If not, I think ND wins by two scores.