I haven't seen a radar trace and don't know what his speed was, but he was from the video I've seen the fastest guy in the sky at the time of the crash.
I'm sure the NTSB will review all the filed exemptions requests and see which ones if any were OK'ed by the FAA. In my youth, I flew heavy iron for Eastern and would pick up extra cash flying for a company that put war birds on static display at airshows east of the Mississippi un and down the East coast all summer long. But I only dropped them off and picked they up I never stayed for the shows.
What ever he was doing it didn't work. and from the video I did see, his excess speed seemed to carry him into the F17. Perhaps to low to dip under, slow and reposition for the B17 if that was his intention, but if he was attempting to close with the P51's he was way out of position and just didn't see the B17.
He may have been a great stick, the best in the world, just not at that moment. stuff happens. That's why I hate airshows, seems like something always happens.