I rarely get self-sown seedlings on Kirengoshoma palmata, in fact, my first ever seedling appeared this spring. The seed pods are as you say, very late to mature, but they also seem particularly susceptible to wet weather, and with some recent rains, I checked the pods and most had turned mushy. Just checked this morning on this bright mild sunny day, and there were three pods with yellowish seed that appears viable, the pods themselves brown and already opened to spill seed, some other pods had already spilled their load. I scratched this seed into the garden around the mother plant. We started getting hard freezes at night starting about 3 weeks ago, and it appears the seed was able to move forward and ripen regardless, although admittedly, this fall has been long, mild, and quite wonderful overall.
So far as Anemonopsis seed, I harvested lots of seed about 3 weeks ago and sowed a couple flats, and about a week ago I took the remaining pods and scratched in seed around the parent plant. The seed ripens over a period of time, some pods ripening sooner than others.