After some more research, it looks like control of the creature only matters for resolution order during the upkeep.
I currently can't think of any way this would happen during the upkeep, so the answer does look to be that Initiative Wins.
What made me ask was the thought that since the creature was dead, it wasn't clear who the controller was, so if that mattered things might get more involved. Turns out, no, not unless there are more ways to raise the dead that can trigger during the upkeep.