score:3
By 1850, transportation of convicts had either ended or was about to end in most parts of Australia. The major exception was Western Australia, to where nearly 10,000 convicts were sent on 43 voyages between 1850 and 1868. They were delivered to the Convict Establishment, which would later be known as Freemantle Prison. Some convicts were imprisoned there long-term but many were put to work, or escaped or were pardoned. Convicts in this era built many public works projects. Those with a ticket of leave were sent to hiring depots, like the one at Lynton and from there to other work sites like copper and lead mines.
The final 1868 arrival mentioned in the question came on the ship Hougoumont. Among the 280 convicts brought on that journey, 62 were Irish political prisoners associated with the Fenian rising of 1867. Nearly a decade later in 1876, six Fenian prisoners famously escaped. I have the sense that they may have been among the last transported convicts to be remaining in prison at that time.