I can answer your 1st and 3rd questions. In regards to Corvus, the only senator by that name that I came across was Marcus Valerius Corvus who enjoyed a very successful political and military career, but lived a few centuries earlier than the destruction of Pompeii, so I would say his portrayal is fictionalized in the film (if you want to learn more on him anyways, I'd suggest The Magistrates of the Roman Republic as one source). The rebellion was based on the rebellion led by Boudica. After the rebels had multiple victories against the Romans, the Roman Suetonius gathered together about 10,000 of his troops while Boudica's men were attacking the city of Verulamium, and despite being vastly outnumbered was able to defeat the rebels. Afterwards, Suetonius continued to put down the rebels but was ultimately replaced by a new governor for fear that he'd spark another rebellion (Boudica: The British Revolt Against Rome AD 60, also the Annals of Tacitus).

The festival was Vulcanalia, which celebrated the Roman god Vulcan, god of fire, volcanoes and forging. It was often celebrated with bonfires and sacrifices, and with all festivals there were often games and feasts. Interestingly, the festival was held around August 23, and Mt. Vesuvius is most commonly believed to have erupted around the 24th, so the festival actually would have been going on around the same time as the eruption (Annals, Greek and Roman Festivals, Roman Festivals of the Period of the Republic). I don't know enough about architecture or sports to answer your other two questions, although there were gladiator fights where the participants re-enacted certain military victories or battles, one such type was the Naumachia where they would re-enact naval battles.