what is interesting about the Phelps family? 1. they turn out to be Tom Sawyer's aunt and uncle; 2. huck discovers they are his real parents; 3. they are related to the two con-men; or 4. Mrs. Phelps is actually Huck's older sister, whom he never met.

Out of the options provided, the most interesting aspect about the Phelps family is that they turn out to be Tom Sawyer's aunt and uncle (option 1). This connection is revealed in Mark Twain's novel "The Adventures of Huckleberry Finn."