Welcome, Moriah. First I'd like to clarify whether you're talking about easy readers or chapter books. Chapter books are short novels for kids who can read independently but can't handle the length or themes of middle grade yet. (lengths are generally 5,000 - 10,0000 words.) Easy readers are for students learning to read. They use controlled structure and vocabulary to aid in the reading process. (Lengths vary depending upon the reading level. Some approach chapter books.) The age group for both overlaps.
There are quite a few twists on the the Three Little Pigs out there. Yours will need to be unique and unexpected to sell.
In terms of comp titles, I'm not coming up with any in either category although Disney may have books in both formats based on their movies. If you have a local children's book store (or section of a book store) or library, you could ask there. They might be able to pint you at what's available out there. Good luck.