Not good. Talk about opposites... Merida would hate how Mulan always does what her parents want and gets frightened easily. she'd like that she dresses as a boy and goes to war but not for the reasons Mulan actually does it. She would wish Mulan actually liked weapons and fighting for amusement, as Merida does. She'd think she's not very fun and is a bit of a wimp, though admire that she saved China. Mulan in turn would find Merida much too fiery and belligerent and might be intimidated by her personality.
It's like fire and water. they're just extremely different.
