Nice to hear from you again. It's been quite some time since I have done any more searching for information re above, but still have not found out anything new.
Quite an interesting history with this lot isn't it.
Very confusing with them using the Wilks surname throughout their lives, making tracing them very difficult indeed.
You certainly have come up with some dare I say 'juicy' tidbits. Henry Cotter Jnr sounds like a nasty piece of work doesn't he.
Hope you are keeping well and 'keep on digging' as they say.
We may yet solve the mystery of John Henry Wilson Snr, though I have heard that records of births and deaths were sometimes not kept at the goldfields (the birth of JHW jr for example).
There was an article in one of the newspapers (Maryborough and Dunolly Advertiser 3 July 1861 I think was the date)(haven't got it to hand at the moment as my papers are boxed while doing some renos) referring to a John Henry Wilson (butcher)at Lamplough being arrested for horse theft in 1861. Couldn't find out what his punishment would have been (? hanging/prison), and as I haven't been able to find a death record I guess that will remain a mystery for some time yet.
As I don't have a lot of resources you may be able to follow that up a bit more.