Just popping in, but Fiera, the Kaballah is known as the Tree of Life, iirc. And M. Brookes was wearing a Ysidril Tree t-shirt when he stated Raxxla is a journey. 2 different trees, but trees of knowledge and life nonetheless.
The Sephirot definitely have some relevance here, at least on a surface level. The “Tree of Life” motif has been shown to pop up with some frequency. I think that it’s reasonable to assume that it will be important.
Kabbalah writ large, however, is far from universal. If Brookes put in the years of study necessary to get Torah, Talmud, and Kabbalah down, then I would be very impressed. It’s not impossible, but it just seems like a lot of work for what probably isn’t that close to his “big picture” when it comes to the ED/Brookes mythos we’re dealing with.
Haven’t really found any Kabbalic references in eg system names, but names of Sephirot would be a good thing to look for. (Although British transliteration of Hebrew tends to be.. not the best, so it can be easy to miss).
Brookes and the ED team seem to be pretty dedicated syncretists, though. So who knows.