The new HomePod mini shares some design elements with the existing HomePod, such as the mesh fabric and the Space Grey and white options, so it's undoubtedly an Apple product, but the new look is quite obviously different to the HomePod.
This isn't a shrunken HomePod. It's got a more spherical design.
As for height: the HomePod is just 3.3in tall compared to the standard HomePod which is 7in.
The company also explains that there is a unique acoustic waveguide that directs sound out the bottom of the speaker, creating a 360‐degree audio field for consistent sound no matter where you are in the room. This is the equivalent to Spatial Awareness - which is a feature that is only available for the HomePod - buy similarly analyzes the acoustics and adjusts the sound based on the speaker's location.