Option 1 is essentially option 2 with more work.
Option 3 could be a not so good idea after all. It depends on whether the fan shroud is tight around the fan. If it isn't, the air flowing through the radiator outside the fan will compete with the air being sucked through the fan when it passes through the exit hole of the shroud. It could lead to a poorer net flow through the radiator.
Could you post a pic?