The spherical treasure chests that are scattered throughout the world exist in the same place regardless of what time period you are in, but once opened, they remain opened in all times. Are the contents always the same regardless of which time period I collect them in? Or are there some that change?
No there is no change in the contents of the spheres. So it doesnt matter in what time you open it. The square boxes are another matter though. Their contents get determined by live sequences where you have the option to answer in multiple ways.