Collin80 sounds like your guy for the controller output!
On the display just be careful because SAE1939 is not the same protocol as OBDII(SAE 1979). I think your best bet for finding out what messages your display is expecting to receive for RPM and Fuel level from the mfg if possible...if you are certain the display is expecting 1939 messages then it will be easy to "emulate" these on one of CAN ports, whilst reading output of your controller on the other. I'll see if i can do digging on what PGN's RPM and Fuel Level live in if this seems worthwhile to you.
Of course the other problem you may run into with your display is scaling, units, etc...which may be hard-coded and not be a 1:1 with what an IC engine.