Is the man in the middle of this photo J C Williamson?
I'm just not sure. JCW was the most famous theatrical entrepreneur in Australian history. He was born in the US and came to Australian the first time in 1874. He made his fortune by acquiring the Australasian rights to Gilbert and Sullivan.
JC Williamson theatres were a household name in Australia until the 1960s.
The photo above has the right provenance to be of JCW and his company. I think the man in the white hat looks like him. Try comparing it to this photo from the National Library of Australia website.