Diligent behavior is indicative of a work ethic; a belief that work is good in itself. It is the counter of sloth.

This one couldn't be more obvious.

^Yup, very obvious.

Snow and Cindy fit this one well too, but Tia's the queen of hard work.

Rapunzel and Snow n Cindy too. But Tiana's multitasking and most hardworking. She tirelessly works for her career and succeeds

Very much so.

Her mantra is work hard.

She is a definition of it.

i find this one more true for Mulan. Tia is just obsessed with it, dont really enjoy it from heart.

Mulan is definitely diligent in training to become a capable soldier.