Well, the Super-Chuffer has run on conventional with a small mod, I have a "test" locomotive with one fitted so I could demonstrate that capability. The Chuff-Generator will work if you have a flywheel and 5V power, no problem with the Super-Chuffer as well.
For DC with the Super-Chuffer, you'd just need a full-wave bridge in front to make sure it has the proper polarity of DC, it's normally expecting AC but only rectifies the positive half cycle. You'd also need at least 7 volts DC track voltage to keep it running.
If I were looking at this environment, I'd probably be thinking of a 9V rechargeable battery with a charging circuit to keep things running during power interruptions or low voltage operation.
If you wanted sounds, I suspect similar measures would have to take place to supply power to the sound board.