First is: Are Akatosh and Auriel different aspects of the time god? are they at odds? does Au-riel align with the Thalmor plot to revert Mundus to it's original state? Is he different from the Akatosh which made the pact with Alessia and created the Dragonborn?
It's hard to tell at this point. Before Skyrim came out, it was generally accepted on the Lore Forum that Akatosh, Alduin, and Auri-El were the same diety. It was also generally accepted that Akatosh was newer than the other two, a construct by Alessia to create a more ideal god for men to worship, and that his dragon imagery was either inspired by Alduin or the Akaviri. One of MK's posts hinted at Alduin and Akatosh being separate, or at least Akatosh working to thwart Alduin, and sure enough when Skyrim came out, we find out that Akatosh is the Dragon' god, known by them as Borhamu, and Alduin is his firstborn son, and the dragons are his children.
In-universe, Auri-El is considered to be the same being as Akatosh, even if he's viewed very differently. A Bosmer who worshiped Auri-El actually joined the Knights of the Nine. Even so, he comes off as being a lot more like Alduin than Akatosh. While Auri-El and Alduin both work to undo creation, Akatosh works to preserve it.