Pre-generated LOD only works for the load order it was generated for. Nobody should be using it and always generate LOD for their personal load order to have LOD match and work as good as it can be.
In FO4 the LOD for trees is part of static object LOD. You need to make sure you have the resources for tree LOD generation for the tree LOD mod(s) installed properly as well. So in this case they might be called object LOD resources, meshes and textures. Typically they should overwrite any of the vanilla LOD resources in the same order as the mod(s) overwrite the full models/textures.
Terrain LOD meshes are made from height data in the plugins and from landscape full textures. So there aren't any LOD resources required. However, there might terrain mods that might have textures only to be used with terrain LOD generation (not sure about FO4, but this exists in Skyrim for example.
AFAIK FAR contains optimized (compression format) vanilla terrain LOD textures and updated detailnormals.dds and noise.dds which are overlayed the terrain LOD textures in the game. If you generate terrain LOD textures with xLODGen they should overwrite the terrain LOD textures from the mod. Keeping the detailnormals.dds and noise.dds from the mod depends on personal preference. They do not affect LOD generation itself.
Water LOD generation is not influenced by mods changing the water textures/shaders. LOD water will use whatever water record is defined on the worldspace record.
The only thing that affects water LOD generation is the worldspace or cell waterhight information or if a cell has water at all.
Edited by sheson, 24 November 2020 - 12:19 PM.