nice design!
can you link the hair? would be nice to see!
you could rehair her in nylon, wrap tiny strands around a needle and heat it to get curls. afterwards, you could pull the locks apart for volume. - but maybeee- is there a shop for kanekalon hair next to you? i would look out for the artificial hair that people really braid into their hair, it does have a similiar texture, i think.
for rehairing, i would use a method where you push the hair from the top into the head and not pull it throught the neckhole.
the no-knot-glue method seems to be the best?