The Power Pals never appeared in any other episodes after this one. It is likely that they died of old age or continued on their journey to the distant planet due to Wet Willie wanting to fight evil where there is water.
Wet Willie is mentioned again on "Something's Fishy!", as a fictional character, star of a superhero movie.
A.J. mentions several real life heavenly bodies when he tells the Power Pals to "take a left at the Andromeda Galaxy, and we're in the third red sun on the left. Oh, and if you hit The Milky Way, you've gone too far." The Milky Way is the galaxy we are currently located in, the Andromeda Galaxy is a galaxy located 2.5 million light years away from Earth, and the red sun may be from the Canis Major Dwarf Galaxy, which is located 25,000 light years away and contains a high percentage of red giant stars.
The 2012 Littlest Pet Shop episode, "Super Sunil" mentions a comic book hero named Super-Sam.
Justice League - The Power Pals are clearly spoofs on some members from the Justice League:
Someone carrying a piano up a long flight of stairs.
Wet Willie wanting to fight crime where there is water.
Timmy forced to wear a maid's outfit.
Timmy's wish was for super friends, but he shouldn't have been able to do that since his godparents made a clear agreement about super wishes. He should have said power pals (like the title of the episode says), not super friends. Although this episode could take place before his godparents made an agreement of not making super wishes.
When the first girl was asking for help, Timmy's buck teeth were missing.