Where can I view the Victory conditions in an online match in Civ 5?
The Civ 5 Victory Progress screen (under the same menu where you access the Diplomacy Overview, etc.) only shows victory conditions that are active in the current game. Methods that are disabled will not even be displayed in the viewer.
(Source: Personal testing. A new game of Civ V is created with the Cultural and Diplomatic Victory conditions disabled. Once in the game, the Victory Progress page is opened, showing only the Space, Domination, and Time Victory condition progress - the ones chosen at the beginning of the game.)