I'd flush immediately, feed with a weak mix of solution C (your most complete fert) and one drop per gallon superthrive. If you flush after the re-pot, all that crap is going to be passing through the fresh soil, you'll need way more water to flush it, and it will just sit there WET because the roots haven't gotten into the new pot yet to use the moisture. And that can lead to rot.

Tehn I would wait until the plants are rather dry and slip the rootball out for a re-pot.

Your first watering after the re-pot should be with the same mix plus 1 tablespoon per gallon unsulfured molasses.