I don't really need to speculate since the report is coming out next month. I didn't even know there was such a thing as the OIG until this whole episode, so no I don't know if they would investigate nothing at all.You really think nothing will come out of the IG investigation? Some FBI guy already got busted for lying and was unceremoniously canned, and that was just about a single leak.
There's a rumor that some US attorney guy is working on something. Does the IG normally waste time with nothing? Do they normally assign a US prosecutor to look at nothing? Maybe Mueller is looking at nothing as well?