I am no expert, by far.
But, I believe that for your project, both are equally up to the task you describe.
I have both, and absolutely have found it to be essential at times. Plus the ease of being able to move from one app to the other while still working on the same project is superb.
But the Export Persona in either should be perfectly suited for your task.
If you want to recreate your yearbook completely from page layout to photo placement, Designer is the way to go.
If you want to do a lot of editing and manipulation of your photos, you may have to tweak them, then Photo is the way to go.
Scanning a sheet, and saving the individual photos as separate files should be perfect for either's Export Persona.
