I finally have what I believe to be authoritative identification of my three Brachychiton trees. I managed to contact Brendan Lepschi, Curator, Australian National Herbarium. He sent this.
"Hi Charles, Lovely images of these plants! Probably the best person to ask about this would be Gordon Guymer at the Queensland Herbarium. He revised the genus and is very familiar with these plants."

      I really appreciate his input. Thank you, Gordon.

      It had all my attention till I was trying to get ahead of some weeds in the back yard and there were two more Brachychitons, one of which was just finishing its blooming. The third one has yet to be observed while blooming. It is the largest one, so I am sure it has bloomed a number of times and I always missed it! (Boo hoo!)

      The #1 Brachychiton bidwillii is still a very small tree and is going to be stunning when it gets some size.

      I planted it a long time ago, perhaps five or more years.

      A Monterey Pine had grown there and had to be removed and the stump ground when it was succumbing to the Bark Beetle. It sat there, put out leaves once a year, a few small flowers, giving promise of great things someday.
      It just sat there and vegetated till this spring. Then it started to grow. I think it has grown at least a foot. Then in late spring it began to lose its leaves and I started to get worried, thinking that I may have finally lost it.

      But then it started to bloom and it became cluttered with bright red trumpets in clusters. The flowers came right out of the wood, even on the trunk!
      It is now August, getting to the end of our summer and the new leaves are emerging. A few flowers are still left. It was a wonderful sight and I'm looking forward to the display when it gets a lot larger. I suspect when the word gets around, people will drive from other parts of town just to see it.
      I am giving you the leaves in full size.