Mord, that is an interesting thought, but I cannot believe that - even if there is something to it (which I doubt) - anyone will ever admit to it.
As far as I know, it would be entirely beyond the FDIC's mandate to help out JPM by taking a piece out of the senior note holders' distribution and giving it to DB. If this hypothetical were even on the radar, I am certain the senior note holders would have filed objections by now. And the FDIC Board had to have a hearing where they inquired into the reasons justifying the settlement before approving.
I just don't see it.