I don't think I have that book, but I'll have a look. My library is a bit chaotic at the moment (too many bloody books, and a big second-hand book sale coming up next week!!).

I haven't seen that fourth verse

I think of poor Edgar and Willie the brave,
Together we oft sang a song;
They're wrapped in the slumber that's found in the grave
Down them In the shades of Toowong.

before, but I have a suspicion that "Willie the brave" is Willie Stone, who was a jockey killed in a fall around 1890, and who is buried in Toowong cemetery in Brisbane. A couple of us, guided by the late Bob Michell, did some research on him a long time ago.

I'll see if I can pick up a likely reference for "Edgar".