Random Lulu observation: Secret-keeper.

It's a tiny detail, but a useful thing to remember for fanfic characterization, and I only just noticed it: Lulu has a habit of knowing people's secrets and keeping them.

-- Yuna's Al Bhed heritage
-- Luzzu telling her about his recruiting Chappu (when Luzzu started to tell Wakka, Lulu tried to stop him)
-- Rikku's Al Bhed heritage from Wakka

Of course, in those three cases, Lulu was trying to prevent Wakka from throwing a conniption. But Lulu also dodged when Tidus asked point blank, "What's... the end [of the pilgrimage]?" She wouldn't give away what Yuna was planning to do, since Yuna was keeping it a secret.