The Impostors Banquet

Story

Blandings Castle has impostors the way some joints have mice. Once again, at a recent dinner there, Lady Constance played hostess to 4 impostors at one sitting! She thought that she was entertaining respected personages named Snipp, Waspshot, Whicker and Pfister, but in fact it was Uncle Fred, Pongo Twistleton, Pauline Stoker and (the usually respectable) Pop Stoker feeding at her trough. Posing as a famous poet, a veterinary expert, a secretary sent by a London agency, and as an opera singer recuperating from laryngitis, this quartet of phony balonies dined in high fashion at the Emsworth table. They had infiltrated Blandings for a number of nefarious motives: one was there to kidnap the Empress, Clarence's prize pig, one was skulking around hoping to find Galahad's memoirs, one hoped to steal away the butler Beach, and one was there just for fun.

Can you determine, from our 5 little clues, who adopted which pseudonym to pose in what role, and for what ulterior motive? And most of all, can you help Beach to seat them in their proper places at the table?

Graphics impaired? The North side of the banquet table seats Constance, Impostor, Impostor (reading from left to right), Clarence is seated at the head of the table on the West side, the South side of the table seats Impostor, Impostor, and Galahad at the Southeast corner.

Clues

1. Pop Stoker sat across the table from "Waspshot", who sat next to the person posing as the Secretary, who sat as far as possible from the impostor who was after the pig.
2. The "Poet" was not after Beach the butler.
3. Lady Constance insisted that Clarence sit by his new "Secretary".
4. Uncle Fred sat right beside the impostor who was after Galahad's memoirs, who sat directly across from "Whicker", who was seated by the "Opera Singer".
5. Pauline was across and one over from "Pfister" and next to the impostor who was there just for fun.