The Great Mouse Detective/WMG

Olivia Flaversham is a robot.
This WMG came from her line: "I don't have a mother". While the implication is that her mother is dead, Hiram Flaversham obviously has a great talent for building incredibly lifelike clockwork mice. She doesn't have a mother because she wasn't born, but rather, built.

Hiram Flaversham is a spark.
This can tie in with the above theory.

Every animated movie involving a Mouse World exists in the same universe.
The Great Mouse Detective takes place in the same universe as An American Tail, The Secret of NIMH, Once Upon a Forest, Chip 'n Dale Rescue Rangers, The Rescuers, possibly Tom and Jerry.
 * Sure Why Not

The setting of the movie will be featured in Kingdom Hearts 3D: Dream Drop Distance

 * Imagine the possibilities!
 * Then I can't wait to see Sora or Riku battling Ratigan.
 * I would actually like to see that, I gotta say.

Basil is a Time Lord

 * Win.