Nothing to worry about with Mancini, at least nothing serious, imo.
Certainly nothing that affects the true and fair view of the accounts which is the central tenet of the PL's case. It just isn't material in view of the losses.
I don't think they have any chance of proving any allegation that implies fraud, either, when there was no FFP and so no benefit to be gained.
The fact that there is no evidence in the public domain to support the al Jazeera connection before Mancini signed for City doesn't mean there isn't any. The leaked emails were for effect, of course, all negative. My theory is Mancini's settlement with Inter prevented him signing full-time for another club for 15 months and so Mansour gave him a consultancy contract with AJ to keep him warm for the City job. Nothing wrong with any of that. Then it was kept on for tax reasons (Mancini's, not ours). Again, nothing wrong with any of that. And, anyway, as pointed out, the rules at the time didn't require disclosure of contracts a manager had with other clubs.
I remember Robbie Savage saying at the time that Khaldoon and Mancini had already worked together and Mancini had been advising him on football. Savage knew Mancini from their time at Leicester, of course. I also found an article in the Guardian when Mancini was signed saying that he and Khaldoon already had a relationship. How else would Mancini have developed a relationship with Khaldoon?
I am thinking this is just another area in which the club has refused to give external information to the PL to justify its position. Once it does that at the panel, the whole thing goes away, imho.
That's assuming it isn't all time barred anyway, which it most probably is. Good luck to the PL proving this was "knowingly concealed" from them.