Definitely wait until blooming is done to consider repotting. Then wait for new growth starting at the base of the plants, that will be the ideal repotting time because it will be making new roots at that time too. During the growing season (spring and summer) keep them on the damp side (not soggy... your new potting medium will give them good drainage). Late fall and winter reduce the water (but not bone dry). At that time you also can put them close to a window to get a bit of chill as well as brighter light - those factors also help with blooming. Starting in early fall, stop all fertilizer. But even during the growing season these are "light feeders" - one of the reasons for getting keikis instead of flowers is too much nitrogen.
Definitely wait until blooming is done to consider repotting. Then wait for new growth starting at the base of the plants, that will be the ideal repotting time because it will be making new roots at that time too.
Thanks for the advice! They already have new growths coming on (see pictures). So should I still wait for the flowers to go, or repot them now before the new roots get going too much?