@TigerMom, have you thought about just upgrading the wheels and/or going with tubeless instead of getting a brand new bike? You might get more weight savings (if that's what you're aiming for) going that route than you would get with a HT. I'm sure there are exceptions, but a lot of the HTs on the market that fit small riders are lower end and heavy.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher