Can I use 1" XPS and fiberglass batts instead of 2" XPS insulation in my basement?
The issue here isn't how well to insulate your basement but it is how to insulate it without trapping water in your walls.

If you double insulated your entire basement you are basically trapping water in your walls Building Science report covers this well.  Water can also sit in fiberglass for a long time - it doesn't dry out fast.  I'm not even proposing that you have a major leak, I am just talking about the normal bleed through concrete.

For your situation I would do the foam board everywhere.  Then I would rock wool to one foot below grade.  So your basement will have different amounts on insulation on different walls.  On a wall that is ground level I would stop a foot off the ground.  Moisture should wick to the bottom and you are giving yourself an air pocket that will help evaporation.  If you feel that you don't want to leave that pocket then I suggest that just the ground level wall gets the 2 inch variety (and I would still rock wool over that).