We can't know for sure how O'Leary would have done; only that he did better than the others. I think he would have adapted as required. While O'Leary had only a slightly higher power ranking, his winning % and average team ranking were a good bit better. But those are only averages, Ross who won an NC was lower on all counts based on averaging.
I understand the "lying"/"carelessness" on the resume being a problem. But for what he was going to do at ND, the resume was only a formality. So I think it really was immaterial except from the appearance aspect. (To get to the top, you have to be good and lucky; his luck ran out.) Everyone knew his record. It seems that GT has had many NCAA issues under many different coaches. That is a different subject