I am so happy to find this forum, I had to register a new account so that I can discuss about giant sequoia!!!
I bought my 2 baby sequoias in June and been repotting them into small tea cups with bonsai soil. When I repotted, I did not more than just a trim so that the root would fit into the pots. They have been growing very well since, I see new shoots on both. However, I also see some yellow and brown foliages. Somehow, those small ones seem to love to be in shade more than under the sun; I am supposed the sun/heat dries them out.
Now that the SoCal is going into "winter," I hope they will do fine. I have been feeding them a little bit of bonsai fertilizers and see them doing well with it. Hopefully they will survive their first winter here...