1. What was the name of Richie Rich's butler?
Cadbury, or to be more specific, Herbert Arthur Runcible Cadbury. IIRC the butler in Richie Rich #1 had a different name; Cadbury became more prominent in the mid-1960s as Richie started branching out into spy stories.
2. Fatso, Fusso and Lazo were better known by what collective nickname?
The Ghostly Trio; they were like the Three Stooges of the ethereal set.
3. In the early 1960s, DC had some success with the Many Loves of Dobie Gillis, based on the popular TV series of the time. Near the end of the Silver Age, DC reused the stories and much of the art (simply erasing the heads) to create what "new" comic?
The Way Out World of Windy and Willie.
4. What long-running DC comic featured the adventures of two toddlers?
Sugar and Spike, created by longtime DC editor Sheldon Mayer, ran for 98 issues.
5. The longest-running comic title today is Detective Comics, but until 1962 that record was held by what comic featuring Woodie Woodpecker, Oswald the Rabbit, and Andy Panda?
New Funnies (originally just The Funnies) was the longest running comic book in history when it published its final issue (#288) in April 1962. After it passed, the title of longest-running comic moved to Adventure Comics (which had undergone name changes from New Comics to New Adventure Comics). When that title folded in 1983, Detective Comics (from which DC gets its name) inherited the mantle.
Joe Bloke kicked major butt on this quiz, correctly getting all five answers. Great job, Joe! Lito S came up with the correct answers for #1, #4 and #5 and also earns our applause.