Leibniz held that each monad mirrored all the others, namely that by knowing all there is to know about each, you knew all there was to know about all. If essentiality of origins holds, then we get Leibniz-like theses quite easily.
1. If essentiality of origins holds, then each thing mirrors everything in its causal history in the strong sense that the proposition that x exists entails the whole causal history of x's coming into existence.
2. If essentiality of origins and determinism holds, and if we add the further postulate that all of the initial conditions for the whole universe are a part of the causal history of every item in the universe's coming into existence, then for every item x in the universe, the proposition that x exists conjoined with the laws entails the whole past, present and future history of the universe.
3. If to the assumptions in (2) we add the postulate that no item in the universe could have existed with the laws being different, then we get the stronger claim that no item in the universe could have existed in any other world—i.e., that the items in the universe are world-bound individuals.
This might make Leibniz's doctrine of mirroring more plausible to some. But I am not a determinist myself.