OK, I've got nothing better to do than consider fictitious crap like this.
Ok, david, can you outline the relevant issues for further discussion.
Major electrical reason why you can't run a Bluebird trailer between Hitachi motors.
Major electrical, weight, braking and structural reasons why you can't run a Hitachi driving trailer push-pull with a loco with U-boat trailers and a dining car in between.
Let's do electrical. We've got a locomotive with a 27 pin jumper which can supply control current but not power for lighting, heating or process heat (Jim's diner). Unless of course the loco will have Head End Power but Jim has not specified what loco he'll be using.
Bluebird cars. Some other kind of jumper coupling altogether. Unless it has a diesel running, no power. Probably needs 120V DC or 76V DC for lighting.
U boat trailer. Uses two 24 pin jumpers dating back to the 1927 "standard" cars (ie Sydney's Red Rattlers). No power generation facilitys. Needs 120V DC for lighting. Has heaters that operate off 1500V DC.
We've got Hitachi cars, which I know very little of. I'm guessing they have a 42 pin jumper. Without overhead there's no source of power here. The (silly?) Victorians never even put batteries in their suburbans until recently. The lights probably need 120 or 240 volts AC but I'd like some Victorian backup on that.
We want to use the Hitachi's as a driving trailer to control the locomotive at the far end of the consist. If we could get an electrical connection through all those dissimilar jumpers we would have to adapt the existing master controller from it's EMU setup (how many notches on a Hitachi?) which would be tricky. There would be switches in the Hitachi cab that could be used for the loco holy trinity, Control/Fuel Pump, Engine Run and Gen field. If there were less than 8 master controller notches you could just pick up every second notch on the engine. You would not really need all eight for an application like this.
So the big problem, as I see it, is that everyone is going to be sitting in the cold and dark because there is no source of heating or lighting power on this train. That's after you standardize the jumper connections.
Got a torch handy, Jim?