Moto G4 and G4 Plus are compatible with Moto Maker, but Moto G4 Play isn't
Announced earlier today, Motorola's Moto G4 family includes three new handsets: Moto G4, Moto G4 Plus, and Moto G4 Play. While all three smartphones are made with budget users in mind, the Moto G4 Play is clearly not on par with the other two, as it's got a 5-inch 720p display (instead of a 5.5-inch 1080p one), and is powered by a quad-core Snapdragon 410 processor (instead of the octa-core Snapdragon 617 that's found inside the G4 and G4 Plus).
Another thing that differentiates the Moto G4 Play from its larger, more powerful siblings is the fact that you won't be able to customize this phone via Moto Maker. Meanwhile, both the G4 and G4 Plus will be available on Moto Maker with the choice of 8 different rear colors, plus various accents, and the option to engrave personalized messages or names on their backs.
source: Motorola US
Things that are NOT allowed: