Micchy Zangetsu Shin makes sense. He's thrown in with the other three Energy Riders and presumably definitively stabs his brother in the back, so what better symbolic gesture is there than to have the little brother take Takatora's place in Yggdrasil's grand bastard hall of fame? At least with the Genesis Driver, as some people here have speculated, there's been no indication that they only bind to one person. Not that it would stop Ryoma from changing his creations anyway.
I don't know what is going on there with the Riotrooper Kurokage with the Genesis Driver. If the prop department is going to be that lazy that even the most basic kitbashing is too much effort to do, why bother?
This is probably the second time I've seen the Buster Sword being used in Toku. White overlord does share some visual aesthetics of Sagara's new getup, but I'm starting to wonder if it's just a red herring. I don't recall Sagara receiving much actual deference from Demushu or Redue when he slithered up to them, while Roshuo seems to. Unless they just can't put 2 and 2 together, but I hope Sagara isn't Roshuo.
Silhouettes look like movie riders. Presumably the Gaim silhouette is like, a Ryuga or something, although we've just had a repaint in the form of Bujin Gaim...