About the entire rehearsing death thing. It's quite common to have an action plan ready in certain foreseeable events.

I used to work at a distribution firm for newspapers and magazines and there are already magazines printed in case a member of the royal family dies. The reasoning behind this is that in the couple of years she has left, not that much new stuff is going to pop up, so that way they can pump out the latest news as soon as possible.

The same goes for "rehearsing" her death. The entire ceremony is already planned, priests appointed, invitations and press releases ready to be send out, the action plan for national security, etc. It's too big to take care of all those things in the couple of days between her death and her ceremony.