There is a possibility that the JD would be fine with the four line pim. I used to keep a 7" pim with a large Red Devil pair without incedent. Though there is that chance things could go bad, you would have to try out to see. Both the bala shark and tin foil are schooling fish. Both get rather large a group of either one would be way to big for a 55g tank. I would suggest rehoming the two and get a group of giant danios as target/dither fish to go along with the JD and pim. Again this would have to be a test, the danios could just end up as lunch.