I think you are almost there. As long as you have fuel to the actual injection pump keep cranking with the lines loose at the injectors. Once a fuel system gets full of air they can be very stubborn to get the air out.
So, I'm about at wits end. I've tried everything I know and can't seem to get it bled, maybe there is something else going on that isn't letting it get bled, IDK. Maybe the newly charged battery will help it crank better and start.