the problem with this logic is its not mutually exclusive as you're portraying it.
If you don't get it, OSU is at the 9 and you still can get 2 TDs and 2 2 pts. If you score and don't get the 2, you're down 10 instead of 13. So in all scenarios, you're at worst down 2 scores still versus you gave yourself the only chance to cut it to one with the catch if you stop them without a 1st down, they're punting out of their end zone.
To me, they were passing the ball well and had drawn multiple flags recently and OSUs defense was gassed.
Trying to say what happened downstream is exactly how it would've played out just isn't accurate given OSU probably doesn't just come out and run it 5 straight times if ND makes the FG.
On an aside, the fake punt was also a horribly telegraphed call given the time and circumstance. It was a great throw that probably should've been caught, but is also what happens when you put backups out there to try make your big plays rather than starters. Don't know why you don't just go for it with your offense given the whole OSU team was aware the fake may be coming. This also handed OSU points.