According to this article, as of June 2020, only 10 victims came forward referring to abuse by Jehovah's Witnesses:
I am surprised the number isn’t zero. The article mentions the number of jw victims (10) who have applied under the national redress scheme. Not much point in applying if Jehovahs Witnesses hasn’t even joined. Presumably the 10 anticipate they will join. The number 1600 is the number of jw victims revealed by its own records subpoenaed by the Royal Commission. The number could be higher.
That being said, I did read elsewhere that overall, claims against those institutions that DID join the national redress scheme lodged so far is well below what was estimated.