And I have no idea what "Forces of Destiny" is, so...
Forces of Destiny is a female-focus web series, that covers all over the franchise. I haven't watched it myself (I've heard that they're
really kiddie and not worth watching), but the relevant episodes are as follows:
Sabine episodes
8 (Sabine and Leia, most likely during Rebels)
9 (Sabine and Ketsu, with appearance by Hera, not sure timeline) (10 on the official YT playlist, because a trailer is counted as episode 9)
13 (Sabine and Jyn, which I believe is where people are getting the "survives Rebels" from) (15 on the official YT playlist, because of the trailer and a compilation of 1-12)
16 (Sabine and Ketsu) (18 on the official YT playlist, because of above)
Hera Episodes
9 (As above, it's mostly Sabine and Ketsu) (again, 10 on the YT list)
14 (Leia orders Han to bargain with Hera to bring rations for the Ewoks, establishing Hera to be alive after RotJ) (16 on the playlist)
Also of note are episode 4, 6, 11, and 12, which are Ahsoka episodes (while she's Anakin's Padawan).
[edit]
Here's the post-RotJ one, I watched it, it's amusing.