Glad to have discussion on bird identification again in this forum.
fkm, for the photos that you've taken, there is no doubt that the first one is APF and the 2nd one is JPF. It's difficult to distinguish between female and juvenile. Since i'm not an expert, i am not going to say anything about this. However, for the "sharp distinction from breast to belly", indeed the bird guide states "Dark ashy-grey breast forms a
fairly sharp pectoral band...". Birders usually say "sharp distinction" when compare between JPF and APF, this is actually a comparative term which means "relatively sharp distinction" rather than sharp like putting a white paper on a blackboard. Actually #2 of your JPF series already showed this characteristic. You can compare #3 of your APF and #2 of JPF, you can see the difference of "diffused" (in APF) and "sharp distinction" (in JPF).
I hope you understand my explanation.
May experts please correct me if I am wrong, thanks!
