These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
In the episode "Newton", Garland has to bail out Lilith and Milo Cawthorne's one-shot character Bolek from an underground toxic waste dump. Fast forward to RPM a few years later, and Rose's character Summer ends up rescuing Olivia's and Milo's characters (Dr. K and Ziggy Grover) from a cave in the episode "If Venjix Won".
Earlier in that episode, Bolek throws a tomato at Lilith. On RPM, Milo's character Ziggy ends up being the Butt Monkey to Olivia's Dr. K, the series' Little Miss Snarker mentor figure. It appears that the pair have experience giving each others' characters a difficult time.
In the episode "Off The Map", Garland agrees to marry the son of the pirate Sultan to keep the solar converter from the wrong hands. In one episode of RPM, Rose's character Summer agrees to go through with her Arranged Marriage to keep the MacGuffin away from the season's Big Bad Venjix. In both cases, it's thankfully subverted.
I Am Not Shazam: The girl protagonist isn't Maddigan; she's Garland Maddigan. The circus is called Maddigan's Fantasia and the show itself is called Maddigan's Quest in reference to the quest that the entire circus takes. (In fact, Maddigan's Fantasia is the title of Margaret Mahy's original book, which was changed when the producers got leery about using the word "Fantasia" and risking copyright problems with the Disney film).