Right. This was my thought process:
"I want to draw angel and devil Nanases to show Nanase's temptation to trash talk Diane."
"Naturally, devil Nanase should be in a sort of traditionally revealing outfit, but I don't want to revealing outfit shame, either. Best give angel Nanase something revealing, too!"
"Wings are awkward. Design around the wings. Ooh, and halo-like bracelets! That'd bring the whole things together."
"Hm. Devil Nanase looks sort of plain now, what with angel Nanase having bracelets. Best give her some accessories, too."
"I may have gone too far, but I sort of love it."
"Ooh, I could make angel Nanase's halo glow a bit! Neat!"
And thus concludes the design journey of a single fantasy panel.
As for the fifth and sixth panels, I was sort of right there with Nanase.
"What would you call a cheerleader Sherlock Holmes? OOH! Sherlock POMPOMS! Wait, that's actually Susan's last name. THANKS, PAST ME, WHAT WERE YOU THINKING?! Well, let's just roll with it."
And for anyone unfamiliar with Holmes, he's the world's most famous fictional detective, and he would sometimes say "elementary, my dear Watson" to his assistant / friend / roommate / possible lover depending on who's at the writing helm, Watson*.
* Never said in the original canon, still famously associated with the character