Carlos, that is a good question. However, I believe the "ethnicfs-vegetation-library" is an object library of specific trees and so on which are simply placed as objects wherever a developer wants to use them. I don't think it has any xml coding that would cause it to alter Asobo's default vegetation. Hopefully, Dmytro, the MSFS Global Trees HD developer can confirm that ethnicfs-vegetation-library would not be a conflict as many user would have this package like you and I do.
I believe that "chrispiaviation_palm_trees_library" is also an object library that would not conflict though I will defer to Dmytro to be sure.
Rod