As explained by Lu to Baga, who told Nini, who told me:
"Tinkerbell, Santa Claus and God all live far away.
Tinkerbell isn't that far — she just lives at Disneyland.
Santa Claus is really far, because he lives at the North Pole.
And God, he lives (gesturing wide with her arms) WAY, WAY far away in heaven. BUT (pointing to her heart) he is always in here."
Her theory sounds like it's only missing the part about how they all three walk into a bar. I have no idea where she comes up with this stuff. All I know is I have talked to her far more about Santa Claus than I have either Tinkerbell or God. She does seem to have them vaguely in the right order, if power is measured by distance. Or something.