Those Australian drawings look as absurd as many other early planes and concepts, but given a sufficient power to weight ratio all manner of aeronautical atrocities can be made to fly:
https://www.youtube.com/watch?v=0rJnXZsrMjU
If this lawn mower were to be proportionally scaled up in size and power it should be capable ofcarrying a person, albeit one even dafter than myself !
Power to weight ratio was the supreme problem for early flights. People like Cayley had already invented the concept (and even the form) of the aeroplane before any powered flights, and given a sufficiently powerful/light engine his designs probably would have worked.
Once the Internal Combustion engine had been invented (as a result of several significant steps by different people) powered flight was inevitable.