That's the thing, isn't it. We don't really know what the detailed allegations actually are.
It's likely the most serious allegations about sponsorship income relate to more than just Etihad and Etisalat and, certainly, for more years with more "evidence" in terms of emails and, possibly, other correspondence.
Then, as you say, they seem to have Mancini, Touré and Fordham on top. And maybe ownership and related party / fair value issues as well. My only concern, really, is if Mansour really did underwrite Fordham's losses - that could be a big number, but I am minded to believe Khaldoon when he says he is confident. It would be a big porkie to claim irrefutable evidence if he knew they were in the wrong.
And, of course, there are different rules on time limitation which may, or may not, come into play.