Depends on the fabric. They make a stripper for fabric that works better then bleach but its really stinky and you might not be able to get all the color out enough to make not purple when you dye it. Also so fabrics wont take dye.
That is true. I've used Rit Color Remover before and that works pretty well too. But yeah, some fabrics just won't dye (synthetic ones I think). And sometimes a piece of clothing will be mixed. So you might have the bulk of the item take the dye, but the stitching won't. Its a lot of trial and error really.
Its hard to say if that jacket in particular will dye or not just based on the picture.