From my personal experience, I have a few comments -
1) The "Chinese style" vocal training doesn't fit most of ABCs here. And something I don't like is that most of Chinese singers especially soprano sings very alike. The "American style" is more focusing on singer's personality.
2) Facial expression/Body expression is very important for singing performance. Drama experience could be big help. I suggest Grace to audition musical children's show hosted in local theatre. You won't be regret the experience. Besides benefit singing performance, my D does great job on Model UN, speech, even the recent Skype interview with George Town Univ. I was watching her and complained that she didn't focus on screen (It looks like she is not looking at interviewers' faces) and she told me that the right way is to "eye contact camera" on iPad. "You'll keep audiences in mind besides keeping yourself in mind, mom". Back to topic, at higher level, students need to learn voice projection. The stage experience will help kids to identify the best location to project their voice.
3) About perfect pitch. Everyone says my D has perfect pitch. Training can improve but can't get to the perfect level. My D can "talk" with birds by whistling. She mimics the birds tone very well. Ask Grace to try it. It's fun. It's always better to have good pitch; but it is not necessary to have good pitch in order to be a welcome singer.
4) Most of people here love Grace. Some express lovingly; some say more directly; but all wish her the best. What we should truly focus is Grace's feeling. If she truly enjoy singing not what we think she enjoys singing, support her. As mom, please watch her not to over stretch her voice cord; and not to let her get hurt mentally; especially getting the pressure from you (even not your intention ). I'll rather having my girls not singing well but love singing instead of can sing well but don't like it. Lots of Asian kids have bad experience on playing piano although they can play so well.
5) I like your thought on letting Grace decides what to do in future (It seems you are a little "pushing" to my impression). Career in this area is much riskier. However, I told my kids that mom has to go with money when choosing major/job but you can afford doing anything you like. Just prepare for the worst. Grace is too young to know too many pros and cons. Let her explore herself. My D has been in singing/musical drama since she was 6. We have wonderful experience. Now she decides not to take music as major (I admit that I "influence" a little) but I believe singing will be always partial of her life.
Just my two cents. I am very alike you that know so little about music / fashion and struggle on how to better help our kids.......It's fun to "grow up" with kids. Hope my two cents help!