Both, probably.

I absolutely <3 both of these Disney beauties, but Mulan gets points since she knew from the beginning she was volunteering to go to war and put herself in harms way.

both are, but I remember Mulan admitting she also did it for herself, if not more for herself (it's been years since I've seen it). Anna didn't choose to get maimed or murdered because she got anything out of it that's for sure. I also thought Anna was fairly unselfish throughout the movie after the party scene. but I don't really like comparing the girls' virtues because they all have different levels of selflessness, bravery, etc.

This girl went above and beyond when it came to helping her sister.

Both, but for completely different themes and reasons.

I agree with AudreyFreak. Mulan's sacrifice is also to bring honour to her family. While Anna's sacrifice is completely selfless cause she doesn't know that she will be thawed.

Mulan had to act like a guy, become a soldier when she didn't know the first thing about wars, risk her life because she could be exposed, risked her life to save Shang, then risked her life again finding Shang and telling him that the Huns are alive.
But Anna is quite selfless too, it's just that the only selfless thing she did was when she stopped Hans from killing Elsa. But I'm not quite sure if she knew she would be turned to ice in that moment.
Lets not forget that she didn't listen to her sister during the Coronation and didn't care to listen to the reason why she didn't want her to be married with Hans. If they talked alone, Elsa would've probably told her. Also when Elsa asked for Anna to give back her glove she didn't do that. I understand why Anna did that , she was tired of not knowing the reason why her sister shut her out all these years but what she did during the coronation was selfish. Also all those years she didn't really care that much about what her sister said, she just wanted to be with her and play with her. Not sure how selfless is that. I do love that says "I'm right out here for you, Just let me in." though.

"you must go after her she could be killed"
"if I reveal her......She will be"
"If the army finds out your a girl the penalty is death"

"an act of true love will thaw a frozen heart"

She KNEW she would die, Mulan only thought there was a chance