Teenage Dream sounds like a Taylor Swift song
Peacock, on the other hand, sounds amazing even with LQ. I think it should be the second single, if not "Futuristic Lover".
I guess "California Gurls", "Teenage Dream" and "Peacock" are the promotional songs from "Teenage Dream" (You know, where she sings a medley of them / full songs on different live shows to promote the album. Like Rihanna with Mad House / Wait Your Turn / Russia Roulette / Hard and Christina Aguilera with Bionic / Not Myself Tonight / Woohoo / You Lost Me.)
These promotional songs are the most important and most effective of Album's first-week sales.