The elves and their goddesses are really closed-off from any other races, in their own private forest. There really isn't contact with many of the other races in order for them to be eligible. I haven't really fleshed out the other races because they aren't relevant to the story; it's a very elf-centric world.
That pseudo-internet idea is definitely something some mycodryads (love that name for them btw) have pulled off. When advanced enough, it can actually be used to achieve full immortality (not just typical elven longevity) by downloading your consciousness into the fungal network. One fungal dryad got literally blown to pieces and survived by storing his consciousness in the mycorrhizal network of the forest for literal years. Most ingenius part of that is that there was absolutely nothing anyone could do about it because they'd essentially have to raze the whole forest to get rid of him.
And no, they're not bound to a specific tree like the more traditional interpretations of dryads. They're more tied to the forest itself rather than a specific tree, and some like the bestial dryads have no real connection to trees at all.