What @LSLGuy said, but I don’t know that there was any conscious effort to draw didn’t the stationery. After all, Her Majesty’s mum was a centenarian, so hard to predict when things might happen.
Plus, a lot of the stationery is now electronic, with the letterhead built into the template, so changing the template doesn’t cost anything.
Yes. The name of the Court changed automatically, effective noon on the day Her Majesty passed on, from Queen’s Bench to King’s Bench.