Oh well I suppose it just comes down to what one likes or dislikes.

I'm not sure how "natural" vibrato is. Most people who come to my choirs have had little or no voice training, and most sing with no vibrato or very little. In fact in my opinion vibrato does not suit choir singing because of the variation of pitch.

Coming back to Jackie, she's obviously had heaps of voice training and she's singing as she's been told by her teachers. I doubt she would get a gig with Celtic Woman! She's going to have problems singing in the school choir, unless she can also sing like the other kids.
I suppose she can always sing a solo.

Andrew