You can replace the blade without removing the radiator - I was surprised to see just how much you can do on the front of the engine without pulling the radiator. The only job I've seen that requires radiator removal is... well, replacing the radiator
You will have to remove the plastic portions in front of the radiator and over the fan - they're held on with clips and are simple to remove.
There are three bolts holding the fan blade onto the viscous clutch. My worksheet doesn't tell me what size, only their torque (10Nm).
Uneven chips in the blades (i.e chips in the individual blades that are not equal in size or position) could lead to problems with the clutch becoming unbalanced as it's spinning. I'd hate to think of the damage done if the blade were to shatter while at highway speeds.