The W-S Lovers appears to me to reflect ideas from the Zohar, including the mystery of sex and earthly matrimony. These are discussed in The Secret Doctrine in Israel and The Holy Kabbalah. Actually there's still a lot about this particular image I'm curious about. The Trinick image reflects Waite's own mysticism more clearly, especially the union of soul and spirit as illustrated by the holding of hands.
I have just been looking at the chapter of the myth of the earthly paradise in the Secret Doctrine of Israel and it interestingly references two gardens of Eden. One located in Binah, part of the supernals of the tree. I think Shekinah at this level is described as being in unification, also, within the world of Atziluth. The lower garden resides in Assiah, the earthly world Malkuth, where there is separation Shekinah is described amongst many other things as being both gardens as well as representing the feminine, womanhood.
I'll need to read it again, at the moment I am wondering if the Trinick Lovers could represent the potential of humanity -the earthly kingdom (garden) to be raised to Binah the higher garden. This would involve getting back the union from the fall where separation occurred. This might be seen in the W.S lovers as depicted through the sex serpent myth and the tree of knowledge on one side and the tree of Life on the other. Possibly the feminine heart Shekinah /soul and spirit/ mind split.
On the Trinick Lovers both trees are entwined at the branches in unity like the figures, whereas on the W.S they are seperated like those figures. I think that the masculine winged figure on the W.S might represent Shekinah in a male aspect because she can be both or either when not united. I think the secret doctrine talked about the possibility that the masculine can not exist without the feminine ( Shekinah) as God is both.
Eta...Maybe the mystic side of Waite is represented by the union with God in it's ideal aspect. The two cards might represent the actual here and now fall and the higher potential to be realised. I might be speculating wildly and getting muddled though it is an interesting read. There seemed to be overlaps with Crowley's views too.