I went in my past works and retrieved a paint shader effect that could help to give a paint realism effect:
Ideas:
Perhaps using UE4 geometry to recreate the main objects shapes (house, lighthouse) and recreate the wall texture from the paint image could solve these parts.
Also the sky could be recreated.
Open Issues:
The grass & rocks, the beach and sea and the main tree are still an open issue on how to generate them with same paint textures.
Also the parts you don’t see in the painting need to be recreated in order to have a fully navigable 3d scenario.