Alduin's Wall features the events of all the previous games as part of the Prophecy of the Dragonborn, so does that mean that all of those events were inevitable? The Elder Scrolls are able to show multiple possible futures meaning that the future in the TES universe is not a certain thing so does that make these events different? Would Alduin have not been able to come back at all if one of them were to have not happened?

I think the events are inevitable. As in, the general outcome. But the specifics may change depending on the flow of time.