I think in all honesty it's one of two rankings for my top 3:
1. Alex
2. Luna
3. Annie
or
1. Luna
2. Alex
3. Annie
(in all honesty I agree with your assessment plus I think to this point Alex is a more guarded personality thanks mainly to her family treating her like she's the step child of the family despite some scenes Axel seems to actually care about her at parts, otherwise it's mainly been her grandma in the one flashback as the only one that cared about her in her family)