I don't know what each letter stands for and from my understanding, you get access to new nodes by reaching the end of a tree for another node. I don't believe you have to fill every point in the tree, just reach a certain point.
I would assume that the entirety of the Cyro tree is in the Cyro path but I can't say for sure. I want to do some more experimenting but mail.ru isn't accepting any of my payment methods for the founder's pack.







