Hmm. Okay. But this is only because you all asked, right? I have tried to keep my time as agenda free as possible, and keep my feelings and opinions of other practitioners to myself, and will endeavour to do the same here, but certain things may spill out simply as a matter of telling the story. Remember, this is my take on how things happened, and are in no way definitive or representative of the feelings or opinions of others. With that said, here we go.
Can anybody tie a story together about when and where the Bujinkan originated in Australia and who actually trained with each other to begin with?
While the list in the OP does include a few of the earliest students, it is not the beginning of the Bujinkan in Australia (or New Zealand, or Papua New Guinea). Your list misses the man who actually did start things here.
In the mid-to-late 70's a young Wayne Lee Roy read a book by Andrew Adams on Ninjutsu, and was intrigued. His father was a boxer, and he had trained in a number of arts since his early teens, including a form of karate, boxing, and Tong Long Kung Fu (Praying Mantis). He began a correspondance with Japan, addressing his letters to Hatsumi Sensei, who passed them on to the most experienced English speaking senior, Toshiro Nagato. Wayne Roy and Nagato Sensei exchanged letters for about a year, with Sensei Roy making his first trip to Japan in 1979. Due to a slight misunderstanding and cultural confusion, as well as a bit of serendipity, Sensei Roy actually spent the first few months living with Nagato Sensei, as well as having him as a teacher.
He later got a job, moved out on his own, and continued to attend the classes. During this first year in Japan, he met Hatsumi Sensei once, at a group meeting which had a number of Westerners involved.
When he returned to Australia, he set about creating the first Bujinkan schools in Brisbane, his home city. Initially, it was basically in a backyard, but soon grew. People came from around the country to learn the art, and Sensei Roy also spent time visiting other cities to give demonstrations and generate interest.
In 1983 he went back to Japan for a year again, this time training directly under Hatsumi Sensei. This included the time when Tanemura Sensei left to form the Genbukan. He was awarded Rokudan as he left.
When he returned, Sensei Roy turned his focus from teaching in a Japanese fashion to teaching in a way that reflected the Australian psychology and the types of violence that are commonly seen here. This began a move away from the Bujinkan mainstream, however he and his organisation remained members of the Bujinkan. When Hatsumi Sensei came out for the first Australian Tai Kai, around 60-65% of all attendees were from his schools. Sensei Roy had created the largest group of Ninjutsu schools in the Southern Hemisphere.
As time went on, though, Sensei Roy's focus on teaching and training in an Australian-focussed way lead to him going to the US to teach and learn with Stephen Hayes, Charles Daniel, Robert Bussey, and more. This of course took precedence over trips to Japan, especially with texts such as the Ten Chi Jin Ryaku no Maki (which he was using to teach from back in the early 80's, well before most of the Bujinkan outside of Hatsumi Sensei, and Charles Daniel who had given Sensei Roy his copy), and the translations of the various densho and makimono (again courtesy of Charles). So he remained a Rokudan, and does to today.
The early students included a few of the names mentioned above. Gillian Booth, for instance, was graded by Sensei Roy to be the first Australian female Ninjutsu black belt. Among the students was a young man who had trained in a sword art (Hokushin Ryu Iaido, I think...), named Ed Lomax. Sensei Roy had been shown very little sword work in Japan, with the focus being more on Hanbo, so he invited Ed to teach him what he knew. He then took Ed's swordwork and created a sword syllabus for his schools training. Ed has never really gotten over this.
He has repeatedly criticised Sensei Roy in a number of publications over the fact that Sensei Roy wasn't shown much sword in Japan, and had to "steal" Eds, which Ed said was something he couldn't respect. Of course, this is all in hindsight now, as Ed stayed with Sensei Roy for a number of years, earning black belt grades with him. Ed later left Sensei Roy, went to Japan, and came back higher ranked and having been told by Hatsumi that he was the Australian representative (according to Ed - I have heard of Hatsumi saying similar to a number of people, basically setting them up against each other... I'm not getting into that, but there are theories about this), and set himself up against Sensei Roy.
In 2000, after a number of his former students had been promoted (very fast) above him, and used this to tear down Sensei Roy and his schools (even though they were all Bujinkan), Sensei Roy left the Bujinkan.
There's a lot more, obviously, but I'm not going into that here. Hopefully this is enough for now. In essence, the origins of the Bujinkan in Australia are Wayne Roy and his schools. Many (but not all) of the major guys in Australia started in his schools, and earnt at least their black belts with him. These days Sensei Roy's organisation is known as Jyukutatsu Dojo (The School of Self Mastery), which reflects his personal approach of utilising martial arts as a vehicle for personal development in all aspects of your life.
