This is one area that I've not yet found time to perform adequate research. But, I believe you may be exactly correct that something from the djed is of importance in the mummification process. Specifically, CO2 may have been caught at the djed and used to provide an oxygen free enviroment for much of the process. Oxygen is rapidly depleted in a decaying organism and most breakdown is done by anaerobic bacteria living primarily in the gastrointestinal tract. By removing the internal organs this is forestalled but it opens up the door for aerobic decomposition. A CO2 atmosphere prevents this.
I'm guessing that stopping all decomposition during the drying period was critical to the process.
This will be very difficult to research. I'm not even sure what questions to ask or of whom. I believe it might have a microbiological answer or means of finding evidence. I seriously doubt anyone has ever investigated this possibility.
Man fears the pyramid, time fears man.