The 2006 reboot takes place in the same universe of that of the original films and the Clouseau played by Steve Martin is actually Jacques Gambrelli, Clouseau's sonAnd the Dreyfus played Kevin Kline is actually the original Dreyfus' (Herbert Lom) nephew, who coincidently is also called Charles.
Clouseau never underwent Magic Plastic SurgeryEither Clouseau was kidnapped or killed and the people responsible for it hired Roger Moore to make the audience believe Clouseau changed his face.
Sir Charles Litton underwent Magic Plastic SurgeryHe had his body changed for the events of Return and reverted to his old one some time thereafter.
Clouseau is GodOr at least God loves him that much, explaining why Clouseau survives the most deadly dangers in the world, everyday.
Dreyfus did not die at the end of Strikes Again.If he did die:
The Ballon mansion was cursed, and the curse could only be broken when only one person remained.For every time Clouseau came close to solving the mystery, another body was found. The explosion at the end ended the curse forever as Maria Gambrelli was all who survived.