I too cringed, reading through this, I would have advised against the chop, but, it worked out. The tree has made a nice recovery. You are ready to do a little branch selection, and toss in a little wire. Nice.
Please stay on top of the insects, they can really set your tree back.
I would not mess with the roots in any way (no repotting, no ''slip potting'') Let the roots recover for at least 12 months after the last repotting. You can keep working the top, just leave the roots alone for a while.
You have a nice start.