No need for WM, for that task, when you know Blender basics.
A heightmap you can even draw with paint, but i would model it inside Blender.https://youtube.com/watch?v=EnrrsVzkqncIf you want to populate your hexfield later (roads/buildings), then i would export them seperately as fbx.
When you set up the origin for all the corresponding “upgradeassets”, then you could easy apply them into UE4
When you need only gfx, from a specific view (not mesh), then you can “bake” your gfx easy and export them.
You could easy export a gfx for each hex with all upgradevariations. For example HexHillSteep.png HexHillSteepRoads.png HexHillSteepRails.png HexHillSteepRoadsRails.png
http://flarerpg.org/tutorials/isometric_intro/