This is a "Wild Mass Guess" entry, where we pull out all the sanity stops on theorizing. The regular entry on this topic is elsewhere. Please see this programme note.
Grand Unifying Guesses Morphing Grid Users
All characters who have "transformations" that consist mostly or entirely a putting on a costume to a sparkly or otherwise unusual background while enemies stand there are tapping into the Morphing Grid
All Pretty Cures, as well as Shiny Luminous (which, as mentioned previously, has the interesting implication that Jesus may secretly have been a Power Ranger) and Milky Rose