Would it make any sense if Young Xehanort is the present day Young Xehanort who just time travelled to try and get Young Eraqus to become one of the thirteen seekers of darkness?
It's possible but I would personally enjoy if it was just a scene showing their lives together in the past. And Xehanort would have to make Eraqus' heart susceptible to the darkness first. Eraqus with his staunch faith in the light would be a lot of work to bring down to that point. I mean they did have to get Sora into a deep dream to make him appropriately vulnerable. Eraqus probably is much harder to break.