During UnrealFest they said it supports rigid movable objects.
I expect foliage has problems beyond alpha/wpo. Namely the fact that 90-100% of the geometry is defining the silhouette and you can’t easily remove any of it without completely destroying its shape. Same reason foliage doesn’t decimate well.
Tileable displacement workflows can be addressed, though I don’t know how easily it would be to integrate it into the engine. Basically just allow the user to tessellate meshes in editor and automatically bake down the displacement in the material to the geometry. You’d probably have to lower the tessellation amount to get near-instant feedback from changes but you could have a “preview setting” and a “built setting” similar to lightmass where you push a button and it builds all the geometry to be high res.