I purchased several azaleas from my local garden center earlier this spring (hybrid cultivars, nothing special: "rosebud," "tradition azalea," "encore amethyst"), and they have long since stopped blooming. Being new to bonsai, I followed the lead of some online guides and videos for azalea bonsai and gave them all a heavy pruning back to a basic desired branch structure after their blooms had finished. It has been about a month or so and they are all showing lots of new growth (the "encore" plant has the most vigorous growth of them all, in case anyone was wondering/looking for a good intro azalea). So far, I have kept them outside, in their nursery pots, and with a layer of sphagnum moss on top to help retain moisture and keep the roots cool from the summer sun.
I am wondering if now would be a good/safe time to replant them into bonsai pots and with a kanuma, akadama, and pumice mixture? I have read elsewhere that it is best to repot Azaleas either in the spring or after they have finished blooming. I live in Pennsylvania, USDA zone 6b. I was planning to over-winter them in my unfinished basement, to protect them from the frost. Any advice?