About DC engines on DCC-managed layouts: my experience, about 22 seconds long, and my reading of the descriptions of others' experiences, is that it isn't a pleasant thing at all. Due to the nature of the signal, its frequent pulses, the DC engine squeals in response, although it improves a bit as the speed of the DC loco increases. I feel that most people give up on that idea pretty quickly. Since some of them must have faster chips upstairs than I have, they would have decided in something less than the 22 seconds it took for me to make up my mind.
However, for the sets that do allow running a DC engine, you have to dial in voltage on your throttle under address "00" to get the engine to run...it won't take off on it's own.
That's really interesting. I would be too confused with all the wiring if I tried to run both. Too bad you don't have a video of that 22 seconds and your face afterword hehe