Stats wise, Ohio are real bad against the run
Looking at the box scores, Penn St ran all over them (6.9ypc). FAU they outscored at home, and FAU is actually a decent team with a good core back from last year. So I don't think they are terrible. But they couldn't throw on PSU. I would guess their o-line is good, but not P5 good, and couldn't give their QB any time to throw on PSU.
I'd expect ISU will be fine as long as special teams are boring (ie competent) and no turnovers. Probably a lot of run game, and Silas/Sanders carries to spread that load around.