You don't think that CASA would have been alerted to a Mayday call being made? Really? This isn't a rumour reaching them, it's ATC receiving a Mayday call from a LCPRT IFR Aircraft that was well within range of ATC, that'd get to them pretty bloody quick I'd dare say!
The SFP can easily be fast tracked depending on the situation and all those details are sitting in an office waiting to be gathered and can be done pretty promptly when a fire is lit under the ass of a Maintenance Organisation who are worried if it's something they did that caused it. They don't take a while to issue an SFP because it takes a certain amount of time to grow on a tree they issue it when it comes up next in the Queue and that queue is dictated by CASA and I've seen dispensations handed out by them pretty quickly when the right person is called for far less reasons in the past. The incident happened at 4.20, so they would have likely still been in the office as well. How often is the CASA office in Broome manned as well I wonder?
You'd also think that the ATSB would be pretty quick to include if an Aircraft had been illegally flown out without the SFP as well wouldn't you? They equally have that fact to hand, if you think they should mention if it was flown out with an SFP then it's equally as likely they'd mention if it didn't have one as required.
As I said Bend Alot, you're making a lot of assumptions and they're to fit the narrative you've already decided upon.