I think there would be plenty of work for a Butcher in 1849, particularly if he had been a shepherd for (Captain) Richard BROOKS of Denham Court and Lake George, in the late 1820s. It is a small step from husbanding sheep to slaughtering sheep.
William BRIGGS, the chap who died 1858, was a brickmaker.
We should also remember that NOT everyone who arrived in New South Wales was transported under a sentence. Perhaps no more than 70% of the population of (penal settlement of) Sydney in the 1828 records was still under a bond. But many were emancipated, others were born in the colony, others were garrison forces and their families and descendants, others were settlers, and others were responding to the opening up of NSW to migration schemes - Grants of Land without Purchase ....
Shipping records for the 1820s are scant on family history for any arrivals except if transported under a sentence of a civil court.
The NSW State Archives has 'ALL' the records. They have released some of these for digitisation by the usual commercial family history websites, and there are kilometres and kilometres of shelving holding far more archives than those commercial websites have digitised. The NSW State Archives online website has many digitised images readily available NO CHARGE, and it has many indexes and a separate search engine for many of each of those indexes. It also has an overall search engine.
I am sure there were about 20 different chaps who were known as William BRIGGS in the late 1820s through to mid 1851 (gold rushes commence mid 1851, tens of thousands of people arrived, no paperwork trail successfully gives all their names as even the shipping clerks caught gold fever and quit Sydney for the long walking trek over the Blue Mountains to the Gold Fields).
NSW State Archives does NOT require membership, does NOT charge entrance fee and is where the original records are held.
https://www.records.nsw.gov.au/I do not have access to Ancestry or Find My Past at present.
My OH and I are hoping to be back at our own home by next weekend. We are still with ancient rellies in Sydney, got ''caught " in June in a very long lockdown. I am relying on one trusty notebook for helping on RChat, and knowing how to get the most out of Trove, NSW State Library e-resources, NLA, etc.
JM