repositionReparent.py

def repositionChildrenToPivot():
	coll = bpy.context.collection
	# Iterate on all object, separate into list of objects, pivot, shadow catcher
	objectList = []
	pivot = None
	shadowCatcher = None
	for c in coll.all_objects:		
		if ("Pivot" in c.name):
			pivot = c
			continue
		if ("ShadowCatcher" in c.name):
			shadowCatcher = c
			continue
		else:
			objectList.append(c)
	
	pLoc = pivot.location
	# Set location of children object to pivot location
	for o in objectList:
		o.location = pLoc
		# Select child then parent object
		bpy.ops.object.select_all(action='DESELECT')
		o.select_set(True)
		pivot.select_set(True)
		bpy.context.view_layer.objects.active = pivot
		bpy.ops.object.parent_set(type='OBJECT')

	#print(pivot.location)
	#print(shadowCatcher)