Yesterday i received an answer regarding translucent z order issues.If you want to read about it (especially my fellow alldogsgotoheaven) here is link : Rendering "Jerkiness" in Unreal (Paper2D) + Translucent Z order issues - Rendering - Epic Developer Community Forums
Now that works in tilemap editor i have a suggestion to make.Please expose per layer in tile map editor.Let us set z order for a layer and whatever enters there it can automatically have that Translucency Sort Priority.It will be so much faster and less prone to mistakes.way it works now is (let me use my favorite word 
) tedious.You have to be really careful what you choose (not easy when you have 12000 sprites in there) and you need to open every blueprint that has a sprite or flipbook and set it manually.And not to mention that if for any reason you want to use that BP on a different Translucency Sort Priority setting you need to make another one!