The part that is banned is using lungs in the recipe. There are many varieties of haggis including vegetarian which substitute parts of the original recipe.
Phil Hartman is the point. The movie features many of San Francisco's attractions so this scene adds to that list and also provides a setting for Charlie to continue his discussion with his best friend about his new relationship.
No. The idea for So I Married an Axe Murderer came from producer Robert N. Fried, who hired writer Robbie Fox to write the script. Principal actor Mike Myers also contributed to the script.