Short answers, pulled from the story.
The Coronation of Napoleon was painted by Jacques-Louis David, the official painter of Napoleon. He completed it in 1807, having begun work on the 21st of December 1805 in the former chapel of the College of Cluny near the Sorbonne, assisted by his student Georges Rouget.
The painting measures almost ten meters wide by a little over six meters tall. It is an oil painting and is currently on display at the Louvre Museum in Paris.
The Coronation of Napoleon is on display at the Louvre Museum in Paris. It was transferred there from the Palace of Versailles in 1889, having previously been stored in the Royal Museums from 1819 to 1837 before being installed at Versailles on the orders of King Louis-Philippe.
No. Pius VII traveled to Notre-Dame de Paris but did not perform the crowning. Napoleon took the crown himself. In David's painting, the pope was adjusted to appear raising his hand in a blessing gesture, emphasizing his ceremonial role and reinforcing the legitimacy Napoleon sought following the Concordat of 1801.
No. Maria Letizia Ramolino did not attend the coronation; she stayed away to protest Napoleon's friction with her sons Lucien and Joseph. David nonetheless placed her in the stands in a position more prominent than the pope's, at her own request.
David painted a full-size replica, commissioned by American entrepreneurs in 1808. He worked from memory and did not finish it until 1822 while living in exile in Brussels. The replica was returned to France in 1947 and is held at the Palace of Versailles. The only deliberate change from the original is the pink dress worn by Napoleon's favorite sister.