Interviews:
The claimed thirteen interview extras are "hidden" Easter eggs that can be found by navigating the menus on the discs as follows:
Disc 1 Easter Egg 1: On "Easter Eggs" menu from "Hint", press your Up button twice
Easter Egg 2: On the main menu from "Episode Selections", press your Up button twice.
Easter Egg 3: On the first "Episode Selections" menu from 2. "Poppy's by the Tree Part I", press your Up button thrice.
Easter Egg 4: On the second "Episode Selections" menu from "Previous Menu" or Left Arrow, press your Up button thrice.
Easter Egg 5: On the third "Episode Selections" menu from 9. "Alley of the Dolls" press your Left button twice.
Easter Egg 6: On the "Trailers" menu from "Main Menu", press your Left button thrice.
Disc 2 Easter Egg 7: On the main menu from "Play All Episodes", press your Down button twice.
Easter Egg 8: On the first "Episode Selections" menu from "Next Menu" or Right Arrow, press your Up button thrice.
Easter Egg 9: On the second "Episode Selections" menu from 13. You Better Watch Out press your Up button twice.
Easter Egg 10: On the third "Episode Selections" menu from the "Return to Main Menu" or Two Curved Arrows press your Down button thrice.
Disc 3 Easter Egg 11: On the main menu from "Episode Selections", press your Up button twice.
Easter Egg 12: On the second Episode Selections" menu from 21. "Father Lode" press your Left button thrice.
Easter Egg 13: Does it exist? I'm inclined to believe it doesn't…