Short answers, pulled from the story.
Legatus Augusti pro praetore was the official title of the governor of certain imperial provinces during the Roman Principate era. The title indicated that the governor was appointed by the emperor rather than elected by the Senate, and the officeholder served simultaneously as the province's chief administrator, head judge, and military commander.
Imperial provinces had their governors selected by the emperor, while senatorial provinces had their governors, called proconsuls, elected by the Roman Senate. By AD 68, fifteen of the empire's thirty-six provinces were imperial, including Britannia, Syria, and the two Germanias.
A legatus Augusti had to be a senator of consular or praetorian rank, meaning he must have previously held the office of consul or praetor. The single exception was the governor of Egypt, the praefectus Aegypti, who was an eques rather than a senator yet still commanded legions.
The praefectus Aegypti was described as unparalleled because the position was held by an eques, a member of the social class between plebeian and patrician, rather than a senator. Despite this lower social rank, the praefectus Aegypti still commanded legions, a combination found nowhere else in the Roman provincial system.
In AD 68, fifteen of the empire's thirty-six provinces were ruled by legati Augusti. They were Hispania Tarraconensis, Lusitania, Gallia Aquitania, Gallia Lugdunensis, Gallia Belgica, Britannia, Germania Inferior, Germania Superior, Moesia, Dalmatia, Galatia, Cappadocia, Lycia et Pamphylia, Syria, and Numidia.
The procurator handled the collection of imperial taxes and revenues, the one function that fell entirely outside the legatus's authority. Unlike the legatus, the procurator did not report to the provincial governor but answered directly to the emperor, serving as an independent financial overseer within the province.