I checked with Ray to find out about #2 and #4.
#2 was a very tiny oscillating cylinder model, Ray remembered it was about 3/16 bore. He decided it was to small to be of much interest and to fiddley to build, so he dropped work on it.
#4 was a a single cylinder, single acting engine of about 3/4" bore, with a piston valve. Ray sold that as a kit with the base metal and plans. It got to be to much work for him in cutting the stock, and the postage charges got to high, so Ray decided not to put it on the web.
#4 was the very first thing I built of metal. In about 1986 I had built a boat to hold an antique, 1908, Gray Single cylinder engine. I took the boat to the New England Museum of Wireless and Steam show, and a guy there had a metal lathe for sale. I bought that lathe, then went looking for a project. Ray was at the show, and I bought the kit for #4. That started me down the trail of metal work, and a lot more machines and models.
Ray is currently working on a better feed pump for his steam powered bicycle.