Michael Palin did not receive an Oscar nomination for portraying Mr Big-Nose, Francis, Mrs A, Ex-leper, Ben, Pontius Pilate, Boring Prophet, Eddie, Nisus Wettus, and the 3rd wise man in Life of Brian.
One of the way that Palin does this is that he makes a far better use of the physical side of his performance than Cleese and Idle do. Palin changes more than just his voice or merely just his lines, but he changes himself with each new character. For example there is when he is Mr. Big-Nose for example he is sure footed and withdrawn as the manner of a man restraining his anger. As the cured leper Palin walks with a particularly strong stand and every movement is especially robust to fully suggest that the man is in the best physical condition. There is also his Pontius Pilate where Palin very brilliantly suggests the previous Pilate portrays as his movements have that stoic quality fitting for the man of the Pilate position. Almost every one of Palin's characters has a different feeling about them, and Palin never just makes it Michael Palin being funny in another costume.
This is a comedic performance though so is he funny. Well yes he is. Palin in fact by physically playing Pilate so "correctly" it makes it all the funnier when he speaks with his speech impediment. The speech impediment would not be funny all by itself, but Palin makes it funny because he still carries Pilate as if he is this great authority figure despite the fact that everyone has to hold back laughter well around him. My favorite of Palin's character here though is as a prison official in charge of telling prisoners where they need to go. Palin creates some pure comedic gold as he keeps the prison official so overly courteous and gentle as he directs various people to their deaths by crucifixion. It only gets better in that these scenes are paired with his Pilate ones making it so Palin just gets to top himself with the amount of laughs he is able to derive with his competing performances.
Michael Palin here does not have any character arcs just characters to have some fun with. In this task he completely succeeds as he is consistently entertaining in his various random appearances throughout the film. He's always a bright spot in his quick appearances, and his largest role of Pilate is one of the true high points of the film. Palin steals this film quite efficiently yet rather modestly with his particular manner of comedic style. Honestly I think Palin probably could have just played all the character and it would have worked out fine as he's so good in creating those different types of characters to make them unique in some way while making sure that he never forgets to be very amusing as well. Palin serves the film with his set of supporting performances probably just as well as he possibly could since he certainly adds plenty of comedy to this comedy.