Azaleas need shade, high humidity and relatively high temperatures (considering the season) when a hard prune is done late winter. Either the right climate, or a greenhouse, or both. Otherwise, wait until overcast days more in the middle of the growing season, or leave some leaves. It is hard to be sure if this one is dead, but like Brian said there are some bad signs, plus it should have started to bud by now. A scratch test likely will show green, but that doesn't mean it is still going to bud. I'd wait a month, then either bin it, or do a scratch test, then bin it if no green. Chinzan is like one of the best varieties for bonsai for those not interested in flower towers.
Repotting a tree that may be dead makes no sense. Just a waste of time. If it makes it, it makes it. If it is barely going to make it, a repot may ruin that. Either repot during a hard prune, or the year after, assuming a perfect response.