In the G1 mythos, Nightbeat was an Autobot detective who loved solving good mysteries. In the comics and cartoons, Nightbeat was often drawn sporting Siren’s “shades” but the toys always depicted him without them.
Rewind is the Autobot archivist, one who records details of events for future generations. More recently in the IDW-verse, Rewind is … erm… married to Chromedome? Or at least that’s how it seems, the term IDW writers used for it is Conjunx Endura. I’ll stick to my original G1 mythos, thanks.
Rewind is a retool of Rumble (who has yet, as of this writing, gotten the Takara treatment)
With his “boss” Blaster.
Titan Masters can “ride” on top thanks to the small pegs.
Comparison with Hasbro Rumble