Several questions: Unwrapping rocks, Billboard LOD creation, Merging "static mesh" actors, etc...

Hi I have a few questions.

(1) How do I properly unwrap a rock inside of blender so there is no UV stretching? I’m still rather new to Blender and the best method I’ve found so far comes from using Mesh->Uv Unwrap->Project from View, but it still leaves a highly stretched texture over a “few” of the triangles in the mesh. I can turn my rocks a certain way to “hide” this effect, but I’d like to know if there’s a better way to do this. I did try using Mesh->Uv Unwrap->Sphere Projection, but that came out even worse looking.

(2) What happens behind the scenes when merging static mesh actors in UE4 to create a new static mesh? For my grass mesh (it’s geometrically based, not alpha mask based), I took my single grass clump (5 grass blades, 20 triangle count), placed 4 of them together in my scene and used Right-Click->Merge Actors to create a grass clump static mesh consisting of 20 grass blades and 80 tris. Is the “end result / render speed in UE4” of this mesh exactly the same as if I were to use Blender to merge 4 small grass clumps into 1 larger grass clump?

(3) This one sort goes along with #2. I was messing around with a small grass clump that I made (this one IS alpha masked and consists of 4 planes / 8 tris). I turned down the foliage paint size of these to a very low size and turned up the density really high so when I paint it onto the landscape with the foliage tool it looks like moss. Now I know this is not a good way of creating a moss effect, but that’s not my point. For something like this is there a render speed effect for drawing 2k of these “instanced” meshes compared to creating the planes in Blender and rendering it as a single mesh? More or less what I’m asking here is if the actual “instance count” causes any performance loss even though they’re instanced into a chunk.

(4) How do you usually go about creating your LOD billboards for distant objects? Do you create them inside your modeling program, or do you do it inside of UE4? I downloaded some trees to use temporarily until I create my own, but the billboards for them look awful and don’t really look like the tree they’re supposed to be representing. If you do your billboards inside of UE4, how do you do it?

My apologies for the odd questions and thanks in advance to anyone who can answer these questions.