Considering it's in a PBE environment, I don't think you can get them. Considering the one you want (Elementalist Lux) is an ultimate skin, I would still give the loot a chance and see if you can get any ultimate skins from it, if you don't get any then you can't get them. Again, it is a PBE environment so there are bound to be changes there that doesn't apply to the live servers.