When middle clicking on the new banner item while in creative, the game will only give you the black banner item and not the item of the banner you middle clicked on. The game only recognizes the black banner as a block, and cannot recognize the banner by it's name, but only its ItemId when trying to use the "/testforblock" command. Banners can be given using their Item name and damage values when using the normal "/give" command.
3 things:
1: pickblock issue has been reported already
2: you got wrong cords you missed by -1x and -1z
3: the code name for the blocks are minecraft:standing_banner and minecraft:wall_banner