* Ulala is the protagonist of the Space Channel 5 series. She is a reporter for Space Channel 5, fighting off alien invaders with her dance moves and charisma.
* Aiai is the protagonist of the Super Monkey Ball series. He's a small monkey who navigates various obstacle courses inside giant rolling spheres.
While these characters are both popular Sega mascots, they've never appeared in the Sonic Riders games. The Sonic Riders games focus primarily on the Sonic the Hedgehog universe, with characters like Sonic, Tails, Knuckles, and others.
It's unlikely that any of the Sonic Riders characters would know anything about Ulala or Aiai. While Sega has a history of crossovers and cameos, these two franchises have remained relatively separate.